Java 注释

最新推荐文章于 2025-03-05 14:03:40 发布

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最新推荐文章于 2025-03-05 14:03:40 发布

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Java 注释

　　五月份得知入职YunOS, 开始学习Java, 断断续续学习和使用Java将近半年, 越来越喜欢这个工具, 因此后来被阿里拥抱变化之后, 拿到的的所有的offer都是Java研发; 一路走来, 踩了很多坑, 也有了一点小小的心得, 那就用博客的形式把他记录下来吧…
　　写的第一篇Java的博客, 就从最基础的Java注释开始!

引

　　程序员圈有一个笑话

最讨厌在写代码的时候写注释, 最讨厌别人的代码里面不写注释

那为啥要写注释呢?
　　我就以自己的亲身经历和理解开始阐述吧:
　　这段时间在微店实习, 最开始干的事情就是将原来北京团队的代码迁移到杭州, 由于更换了技术架构, 因此很多代码都需要重写. 但是重写的首先要理解原先的业务逻辑, 当我在SVN(对, 你没有看错, 就是SVN -_-!!)上把代码拉下来, 看到几千行代码里面只有寥寥几行注释时, 我愣了…
　　另一个我经常遇到的事情, 有的时候自己写的代码有Bug, 或者可能需要重构, 这时需要review自己的代码, 可是突然发现自己已经很难理解原有的编程思路, 甚至这段代码可能就是昨天才刚刚写过的, 但是已经很难回到当时写代码的状态了.
　　还有一个重要的原因就是代码即文档, 有些时候, 文档的更新速度相对落后, 在这种情况下, 我们解决问题只能直接看代码, 如果一个人的代码写的规范, 模块划分合理, 注释详尽清晰, 其实完全可以起到文档的作用.
　　因此后来在自己写代码的时候就强迫自己写注释, 虽然并未按照下面介绍的注释规范, 但是我尽量用最简单的语言把问题阐述清楚, 在代码看起来难懂的地方加上清晰的注释, 这样后来再看代码的时候(无论是自己还是代码的接收人)就没有必要一行一行的跟踪代码了.

Java三种注释类型

　　Java提供三种注释: 单行注释, 多行注释, 文档注释.
1.单行/多行注释
　　单行注释与多行注释的作用与用法就不再赘述了, IDEA快捷键分别如下:
　　 command+/: 以//快速注释一行或多行 :

<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//        Integer[] array = new Integer[10];</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//        for (int i = 0; i < array.length; ++i){</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//            array[i] = new Integer(i);</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//        }</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

　　command+option+/: 以/**/快速注释一行或多行

<code class="hljs vbscript has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">/*
        Integer[] <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">array</span> = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Integer[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">10</span>];
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">int</span> i = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>; i < <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">array</span>.length; ++i){
            <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">array</span>[i] = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Integer(i);
        }
*/</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>

2.文档注释
　　Java语言提供了一种功能非常强大的注释形式: 文档注释. 如果编写Java源代码时添加了合适的文档注释, 然后通过JDK提供的javadoc工具就可以直接将代码里的注释提取成一份系统的API文档. 其注释形式为/** */

<code class="hljs applescript has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">    /**
     * Initializes a newly created {@code String} object so <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">that</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">it</span> represents
     * <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span> same sequence <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">of</span> <span class="hljs-property" style="box-sizing: border-box;">characters</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">as</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span> argument; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">in</span> other <span class="hljs-property" style="box-sizing: border-box;">words</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span>
     * newly created <span class="hljs-type" style="box-sizing: border-box;">string</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">is</span> a <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">copy</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">of</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span> argument <span class="hljs-type" style="box-sizing: border-box;">string</span>. Unless an
     * explicit <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">copy</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">of</span> {@code original} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">is</span> needed, use <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">of</span> this constructor <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">is</span>
     * unnecessary <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">since</span> Strings are immutable.
     *
     * @param  original
     *         A {@code String}
     */</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li></ul>

# javadoc 注释标签语法

标签	作用域	说明
@author	类	标明开发该类模块作者
@version	类	标明该类模块的版本
@see	类, 属性, 方法	参考转向(相关主题)
@param	方法	对方法中某参数的说明
@return	方法	对方法返回值的说明
@exception	方法	抛出的异常类型
@throws	方法	与@exception相同
@deprecated	方法	不建议使用该方法

Java代码注释原则

下面是我从网上看到和自己总结的代码注释原则,

1. 注释准确简洁(最重要)
　　内容要简单明了、含义准确, 尽量用最少的语言把问题阐述清楚, 防止注释的多义性，错误的注释不但无益反而有害.
2. 避免复杂的注释
　　如果需要用复杂的注释来解释复杂的代码，请检查此代码是否应该重写。尽一切可能不注释难以理解的代码，而应该重写它.
3. TODO List
　　为尚未完成的代码添加TODO注释, 提醒自己这段代码还需要后续完善.
4. 注释形式统一
　　在整个项目中，使用一致的结构样式来构造注释.
5. 注释与代码同步更新
　　在写代码之前或边写代码边注释，因为以后很可能没有时间来写注释了(如果有机会review已写的代码，可能在今天看来很明显的东西六周以后或许就不明显了)。通常描述性注释先于代码创建，解释性注释在开发过程中创建，提示性注释在代码完成之后创建。修改代码的同时修改相应的注释，以保证代码与注释的同步.
6. 注释就近原则
　　保证注释与其描述的代码相邻, 在代码上方或右方(最好上方)进行注释.
7. 注释不要过多
　　注释必不可少，但也不应过多，注释占程序代码的比例达到20%左右为宜。注释是对代码的“提示”，而不是文档，如果代码本来就是清楚、一目了然就不加注释，而且注释的花样要少。
8. 删除无用注释
　　在代码交付或部署发布之前，必须删掉临时或无关的注释，以避免在日后的维护工作中产生混乱。
9. 必加注释之处
　　- 典型算法必须有注释。
　　- 在代码不明晰处必须有注释。
　　- 在循环和逻辑分支组成的代码中加注释。
　　- 为他人提供的接口必须加详细注释。
　　- 在代码修改处加上修改标识的注释

JDK注释参考:

类/接口注释

<code class="hljs php has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
 * The <code>String</code> class represents character strings. All
 * string literals in Java programs, such as <code>"abc"</code>, are
 * implemented as instances of this class.
 * (其他描述)
 *<span class="hljs-phpdoc" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @author</span>  Lee Boynton
 *<span class="hljs-phpdoc" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @author</span>  Arthur van Hoff
 *<span class="hljs-phpdoc" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @author</span>  Martin Buchholz
 *<span class="hljs-phpdoc" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @author</span>  Ulf Zibis
 *<span class="hljs-phpdoc" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @see</span>     java.lang.Object#toString()
 *<span class="hljs-phpdoc" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @see</span>     java.lang.StringBuffer
 *<span class="hljs-phpdoc" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @see</span>     java.lang.StringBuilder
 *<span class="hljs-phpdoc" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @see</span>     java.nio.charset.Charset
 *<span class="hljs-phpdoc" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @since</span>   JDK1.0
 */</span>

 <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">String</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">java</span>.<span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">io</span>.<span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Serializable</span>, <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Comparable</span><<span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">String</span>>, <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">CharSequence</span> {</span>
    ...
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul>

构造方法注释

<code class="hljs applescript has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">    /**
     * Initializes a newly created {@code String} object so <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">that</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">it</span> represents
     * <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span> same sequence <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">of</span> <span class="hljs-property" style="box-sizing: border-box;">characters</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">as</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span> argument; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">in</span> other <span class="hljs-property" style="box-sizing: border-box;">words</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span>
     * newly created <span class="hljs-type" style="box-sizing: border-box;">string</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">is</span> a <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">copy</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">of</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">the</span> argument <span class="hljs-type" style="box-sizing: border-box;">string</span>. Unless an
     * explicit <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">copy</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">of</span> {@code original} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">is</span> needed, use <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">of</span> this constructor <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">is</span>
     * unnecessary <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">since</span> Strings are immutable.
     *
     * @param  original
     *         A {@code String}
     */
    public String(String original) {
        this.value = original.value;
        this.hash = original.hash;
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li></ul>

方法注释

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
     * Returns <tt>true</tt> if, and only if, {@link #length()} is <tt>0</tt>.
     *
     *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @return</span> <tt>true</tt> if {@link #length()} is <tt>0</tt>, otherwise
     * <tt>false</tt>
     *
     *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @since</span> 1.6
     */</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> <span class="hljs-title" style="box-sizing: border-box;">isEmpty</span>() {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> value.length == <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li></ul>

字段/属性注释

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** The value is used for character storage. */</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span> value[];

    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** Cache the hash code for the string */</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> hash; <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Default to 0</span>

    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** use serialVersionUID from JDK 1.0.2 for interoperability */</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">long</span> serialVersionUID = -<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">6849794470754667710</span>L;

    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
     * Class String is special cased within the Serialization Stream Protocol.
     *
     * A String instance is written initially into an ObjectOutputStream in the
     * following format:
     * <pre>
     *      <code>TC_STRING</code> (utf String)
     * </pre>
     * The String is written by method <code>DataOutput.writeUTF</code>.
     * A new handle is generated to  refer to all future references to the
     * string instance within the stream.
     */</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> ObjectStreamField[] serialPersistentFields =
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> ObjectStreamField[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>];</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li></ul>

方法内的注释

<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> boolean <span class="hljs-title" style="box-sizing: border-box;">regionMatches</span>(boolean ignoreCase, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> toffset,
            String other, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> ooffset, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> len) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span> ta[] = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>;
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> to = toffset;
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span> pa[] = other.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>;
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> po = ooffset;
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Note: toffset, ooffset, or len might be near -1>>>1.</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> ((ooffset < <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) || (toffset < <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>)
                || (toffset > (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">long</span>)<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>.length - len)
                || (ooffset > (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">long</span>)other.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>.length - len)) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;
        }
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span> (len-- > <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span> c1 = ta[to++];
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span> c2 = pa[po++];
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (c1 == c2) {
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">continue</span>;
            }
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (ignoreCase) {
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// If characters don't match but case may be ignored,</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// try converting both characters to uppercase.</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// If the results match, then the comparison scan should</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// continue.</span>
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span> u1 = Character.toUpperCase(c1);
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span> u2 = Character.toUpperCase(c2);
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (u1 == u2) {
                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">continue</span>;
                }
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Unfortunately, conversion to uppercase does not work properly</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// for the Georgian alphabet, which has strange rules about case</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// conversion.  So we need to make one last check before</span>
                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// exiting.</span>
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (Character.toLowerCase(u1) == Character.toLowerCase(u2)) {
                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">continue</span>;
                }
            }
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;
        }
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;
    }

    String(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span>[] <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>, boolean share) {
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// assert share : "unshared not supported";</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span> = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>;
    }

    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span>[] val = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>;   <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/* avoid getfield opcode */</span>

    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> boolean <span class="hljs-title" style="box-sizing: border-box;">contentEquals</span>(CharSequence cs) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>.length != cs.length())
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Argument is a StringBuffer, StringBuilder</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (cs instanceof AbstractStringBuilder) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span> v1[] = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>;
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span> v2[] = ((AbstractStringBuilder) cs).getValue();
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> n = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>.length;
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span> (n-- != <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (v1[i] != v2[i])
                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;
                i++;
            }
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;
        }
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Argument is a String</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (cs.equals(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>))
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Argument is a generic CharSequence</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">char</span> v1[] = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>;
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> n = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">value</span>.length;
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span> (n-- != <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (v1[i] != cs.charAt(i))
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;
            i++;
        }
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li><li style="box-sizing: border-box; padding: 0px 5px;">52</li><li style="box-sizing: border-box; padding: 0px 5px;">53</li><li style="box-sizing: border-box; padding: 0px 5px;">54</li><li style="box-sizing: border-box; padding: 0px 5px;">55</li><li style="box-sizing: border-box; padding: 0px 5px;">56</li><li style="box-sizing: border-box; padding: 0px 5px;">57</li><li style="box-sizing: border-box; padding: 0px 5px;">58</li><li style="box-sizing: border-box; padding: 0px 5px;">59</li><li style="box-sizing: border-box; padding: 0px 5px;">60</li><li style="box-sizing: border-box; padding: 0px 5px;">61</li><li style="box-sizing: border-box; padding: 0px 5px;">62</li><li style="box-sizing: border-box; padding: 0px 5px;">63</li><li style="box-sizing: border-box; padding: 0px 5px;">64</li><li style="box-sizing: border-box; padding: 0px 5px;">65</li><li style="box-sizing: border-box; padding: 0px 5px;">66</li><li style="box-sizing: border-box; padding: 0px 5px;">67</li><li style="box-sizing: border-box; padding: 0px 5px;">68</li><li style="box-sizing: border-box; padding: 0px 5px;">69</li><li style="box-sizing: border-box; padding: 0px 5px;">70</li><li style="box-sizing: border-box; padding: 0px 5px;">71</li><li style="box-sizing: border-box; padding: 0px 5px;">72</li><li style="box-sizing: border-box; padding: 0px 5px;">73</li><li style="box-sizing: border-box; padding: 0px 5px;">74</li><li style="box-sizing: border-box; padding: 0px 5px;">75</li><li style="box-sizing: border-box; padding: 0px 5px;">76</li><li style="box-sizing: border-box; padding: 0px 5px;">77</li><li style="box-sizing: border-box; padding: 0px 5px;">78</li></ul>

附: 开发者工具

IDEA: 一款比较给力的Java IDE, 用过都说好(我师兄说:”自从用了IDEA, 写代码越来越有劲儿了”). 有很多很赞的功能, 比如对Git与Maven的支持, 智能的代码提示, 自带命令行工具, 黑色的主题(比较适合zhuangbility)… 但是商业版本比较贵, 不过有社区开源版本; 而且现在IDEA家族现在变得越来越强了, Android Studio就是基于该IntelliJ IDEA的开源版本版本进行Android定制开发的, 而且现在IDEA又出了C/C++版本 CLion, 当年我还在写C/C++的时候听说过这款IDE, 不过没怎么用, 大致浏览了一下, 感觉还是挺酷的.
Git&GitHub: GitHub作为全球最大同性交友网站就不用多做介绍了, 而Git则算是互联网开发者居家旅行必备吧. 这方面我看过视频, 也看过书, 不过我在这里只推荐一部文档, 虽然Git内容很多, 但是大部分知识感觉是三五年内用不到的, 而这一篇文档却直取要害, 非常实用, 读了很多遍,原文链接.
Maven: 在阿里, 开发Java项目要遵守Maven的规范, 我个人也比较喜欢使用Maven构建Java项目, 最起码不用把Jar包拷贝过来拷贝过去了. 不过这方面我也是新手, 因此在这里我只推荐一部还不错的Maven方面的书, Maven实战, 一部国人写的非常棒的实战类书籍, 让我对国人写的技术书籍重拾信心.
MySQL-Workbench: 一款MySQL的GUI客户端, 在Mac上感觉是用的最爽的一个了, 以前用过几个版本的Navicat, 数据库表一旦大了之后就变得很卡, 而workbench则完全没有问题, 而且灰色的主题也比较护眼.
ProcessOn: 一个绘图的网址, 可以绘制一些UML图之类的, 上手容易.
Markdown: 这个就不多说了, 我也是初学者, 好像现在写博客的技术人员都在用, 本篇博客也是我用Markdown写的第一篇博客.
再推荐几个JSON查看与编辑的网站:
- qqe2.com, 这个网站对JSON数据的排错提示功能很强大;
- json.cn, 查看JSON数据非常美观, 支持代码折叠. JSON方面没有发现比较好用的客户端, 希望知道的同学可以推荐几个.