SpringBoot 进阶

本文详述了SpringBoot如何整合Mybatis,包括自动配置、连接池的设置,以及SpringBoot的事务管理、单元测试、MVC功能和异常处理机制。此外,还介绍了SpringBoot的定时任务配置与Cron表达式的使用,以及项目打包成jar的步骤。

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目录

一、SpringBoot 整合 Mybatis

1、SpringBoot 整合 Mybatis

2、SpringBoot 整合连接池

2.1、spring-boot-starter-jdbc

2.2、配置druid

3、SpringBoot整合事务

二、SpringBoot单元测试

1、引入启动器

2、测试方式1

3、测试方式2

三、SpringBoot整合MVC

1、访问静态资源

四、SpringBoot异常处理

1、默认方式

2、@ExceptionHandle 注解方式

3、@ControllerAdvice方式

五、SpringBoot定时任务

1、 引入依赖

2、编写定时任务

3、 开启定时任务注解

4、Cron 表达式

六,打包

1、打jar包


一、SpringBoot 整合 Mybatis

1、SpringBoot 整合 Mybatis

MyBatis 帮助我们快速集成 SpringBoot 提供的一个组件包(mybatis-spring-boot-starter),使用这个组件可以做到以下几点:

  • 自动检测现有的DataSource

  • 将创建并注册SqlSessionFactory的实例,该实例使用SqlSessionFactoryBean将该DataSource作为输入进行传递,将创建并注册从SqlSessionFactory中获取的SqlSessionTemplate的实例。

  • 自动扫描您的mappers,将它们链接到SqlSessionTemplate并将其注册到Spring上下文,以便将它们注入到您的bean中

使用了该Starter之后,只需要定义一个DataSource即可(application.properties或application.yml中可配置),它会自动创建使用该DataSource的SqlSessionFactoryBean以及SqlSessionTemplate。会自动扫描你的Mappers,连接到SqlSessionTemplate,并注册到Spring上下文中。

SpringBoot官⽅并没有提供Mybatis的启动器,不过Mybatis官⽅⾃⼰实现了:

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#aa5500"><!--mybaits与springboot整合--></span>
<span style="color:#117700"><</span><span style="color:#117700">dependency</span><span style="color:#117700">></span>
    <span style="color:#117700"><</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>org.mybatis.spring.boot<span style="color:#117700"></</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>
    <span style="color:#117700"><</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>mybatis-spring-boot-starter<span style="color:#117700"></</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>
    <span style="color:#117700"><</span><span style="color:#117700">version</span><span style="color:#117700">></span>2.2.0<span style="color:#117700"></</span><span style="color:#117700">version</span><span style="color:#117700">></span>
<span style="color:#117700"></</span><span style="color:#117700">dependency</span><span style="color:#117700">></span></span></span>

配置mapper扫描路径和日志

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#0000ff">spring</span>:
<span style="color:#0000ff">  datasource</span>:
<span style="color:#0000ff">    driver-class-name</span>:<span style="color:#009900"> com.mysql.cj.jdbc.Driver</span>
<span style="color:#0000ff">    url</span>:<span style="color:#009900"> jdbc</span>:<span style="color:#009900">mysql</span>:<span style="color:#009900">//127.0.0.1</span>:<span style="color:#009900">3306/test?useUnicode</span>=<span style="color:#009900">true&characterEncoding</span>=<span style="color:#009900">utf-8&serverTimezone</span>=<span style="color:#009900">UTC</span>
<span style="color:#0000ff">    username</span>:<span style="color:#009900"> root</span>
<span style="color:#0000ff">    password</span>:<span style="color:#009900"> 123456</span>
<span style="color:#0000ff">mybatis</span>:
<span style="color:#0000ff">  mapper-locations</span>:<span style="color:#009900"> classpath</span>:<span style="color:#009900">mapper/*Dao.xml</span>
​
<span style="color:#0000ff">logging</span>:
<span style="color:#0000ff">  level</span>:
<span style="color:#0000ff">    com.woniu.dao</span>:<span style="color:#009900"> debug</span>
<span style="color:#0000ff">  pattern</span>:
<span style="color:#0000ff">    console</span>:<span style="color:#009900"> '%d{yyyy-MM-dd HH</span>:<span style="color:#009900">mm</span>:<span style="color:#009900">ss.SSS} [%thread] %-5level %logger{50} - %msg%n'</span></span></span>

在启动类上添加@MapperScan,扫描到dao接口路径, 或者在每个dao接口上添加@Mapper注解,但是建议使用启动类上注解例如:

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#555555">@SpringBootApplication</span>
<span style="color:#555555">@MapperScan</span>(<span style="color:#aa1111">"cn.woniu.dao"</span>) <span style="color:#aa5500">//自己项目dao接口路径</span>
<span style="color:#770088">public</span> <span style="color:#770088">class</span> <span style="color:#0000ff">SpringbootAplication</span> {
    <span style="color:#770088">public</span> <span style="color:#770088">static</span> <span style="color:#008855">void</span> <span style="color:#000000">main</span>(<span style="color:#008855">String</span>[] <span style="color:#000000">args</span>) {
        <span style="color:#000000">SpringApplication</span>.<span style="color:#000000">run</span>(<span style="color:#000000">SpringbootAplication</span>.<span style="color:#770088">class</span>, <span style="color:#000000">args</span>);
    }
}</span></span>

编写mapper文件下xml文件

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#555555"><?xml</span> <span style="color:#555555">version="1.0" encoding="UTF-8" ?></span>
<span style="color:#555555"><!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" ></span>
<span style="color:#117700"><</span><span style="color:#117700">mapper</span> <span style="color:#0000cc">namespace</span>=<span style="color:#aa1111">"cn.woniu.dao.UserDao"</span><span style="color:#117700">></span>
   <span style="color:#117700"><</span><span style="color:#117700">select</span> <span style="color:#0000cc">id</span>=<span style="color:#aa1111">"getUser"</span> <span style="color:#0000cc">resultType</span>=<span style="color:#aa1111">"cn.woniu.domain.User"</span><span style="color:#117700">></span>
      select username,password from user
   <span style="color:#117700"></</span><span style="color:#117700">select</span><span style="color:#117700">></span>
<span style="color:#117700"></</span><span style="color:#117700">mapper</span><span style="color:#117700">></span></span></span>

2、SpringBoot 整合连接池

2.1、spring-boot-starter-jdbc

从 Spring Boot 2.0 开始,spring-boot-starter-jdbc内部提供了默认的 HikariCP 数据库连接池,(也是传说中最快的数据库连接池)。spring-boot-starter-jdbc主要提供了三个功能,第一个就是对数据源的装配,第二个就是提供一个JdbcTemplate简化使用,第三个就是事务

a、关键依赖包

<span style="background-color:#f8f8f8"><span style="color:#333333">   <span style="color:#117700"><</span><span style="color:#117700">parent</span><span style="color:#117700">></span>
        <span style="color:#117700"><</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>org.springframework.boot<span style="color:#117700"></</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>
        <span style="color:#117700"><</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>spring-boot-starter-parent<span style="color:#117700"></</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>
        <span style="color:#117700"><</span><span style="color:#117700">version</span><span style="color:#117700">></span>2.5.4<span style="color:#117700"></</span><span style="color:#117700">version</span><span style="color:#117700">></span>
    <span style="color:#117700"></</span><span style="color:#117700">parent</span><span style="color:#117700">></span>
​
    <span style="color:#117700"><</span><span style="color:#117700">dependencies</span><span style="color:#117700">></span>
        <span style="color:#aa5500"><!--springmvc启动器--></span>
        <span style="color:#117700"><</span><span style="color:#117700">dependency</span><span style="color:#117700">></span>
            <span style="color:#117700"><</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>org.springframework.boot<span style="color:#117700"></</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>
            <span style="color:#117700"><</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>spring-boot-starter-web<span style="color:#117700"></</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>
        <span style="color:#117700"></</span><span style="color:#117700">dependency</span><span style="color:#117700">></span>
        <span style="color:#aa5500"><!--mysql驱动--></span>
        <span style="color:#117700"><</span><span style="color:#117700">dependency</span><span style="color:#117700">></span>
            <span style="color:#117700"><</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>mysql<span style="color:#117700"></</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>
            <span style="color:#117700"><</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>mysql-connector-java<span style="color:#117700"></</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>
            <span style="color:#117700"><</span><span style="color:#117700">scope</span><span style="color:#117700">></span>runtime<span style="color:#117700"></</span><span style="color:#117700">scope</span><span style="color:#117700">></span>
        <span style="color:#117700"></</span><span style="color:#117700">dependency</span><span style="color:#117700">></span>
        <span style="color:#aa5500"><!--spring默认数据库连接池--></span>
        <span style="color:#117700"><</span><span style="color:#117700">dependency</span><span style="color:#117700">></span>
            <span style="color:#117700"><</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>org.springframework.boot<span style="color:#117700"></</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>
            <span style="color:#117700"><</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>spring-boot-starter-jdbc<span style="color:#117700"></</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>
        <span style="color:#117700"></</span><span style="color:#117700">dependency</span><span style="color:#117700">></span>
    <span style="color:#117700"></</span><span style="color:#117700">dependencies</span><span style="color:#117700">></span></span></span>

b、创建springboot的配置文件application.properties

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#aa5500"># 连接四⼤参数</span>
<span style="color:#0000ff">spring.datasource.driver-class-name</span>=<span style="color:#009900">com.mysql.cj.jdbc.Driver</span>
<span style="color:#0000ff">spring.datasource.url</span>=<span style="color:#009900">jdbc</span>:<span style="color:#009900">mysql</span>:<span style="color:#009900">//127.0.0.1</span>:<span style="color:#009900">3306/test?useUnicode</span>=<span style="color:#009900">true&characterEncoding</span>=<span style="color:#009900">utf-8&serverTimezone</span>=<span style="color:#009900">UTC</span>
<span style="color:#0000ff">spring.datasource.username</span>=<span style="color:#009900">root</span>
<span style="color:#0000ff">spring.datasource.password</span>=<span style="color:#009900">123456</span>
<span style="color:#aa5500">#连接池信息</span>
<span style="color:#0000ff">spring.datasource.hikari.idle-timeout</span>=<span style="color:#009900">60000</span>
<span style="color:#0000ff">spring.datasource.hikari.maximum-pool-size</span>=<span style="color:#009900">30</span>
<span style="color:#0000ff">spring.datasource.hikari.minimum-idle</span>=<span style="color:#009900">10</span></span></span>

2.2、配置druid

  • 配置druid

    如果你更喜欢Druid连接池,也可以使⽤Druid官⽅提供的启动器,那麼就不需要spring-boot-starter-jdbc启动器了。

    <span style="background-color:#f8f8f8"><span style="color:#aa5500"><!-- Druid连接池 --></span>
    <span style="color:#117700"><</span><span style="color:#117700">dependency</span><span style="color:#117700">></span> 
      <span style="color:#117700"><</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>com.alibaba<span style="color:#117700"></</span><span style="color:#117700">groupId</span><span style="color:#117700">></span> 
      <span style="color:#117700"><</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>druid-spring-boot-starter<span style="color:#117700"></</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span> 
      <span style="color:#117700"><</span><span style="color:#117700">version</span><span style="color:#117700">></span>1.1.10<span style="color:#117700"></</span><span style="color:#117700">version</span><span style="color:#117700">></span>
    <span style="color:#117700"></</span><span style="color:#117700">dependency</span><span style="color:#117700">></span></span>

    ⽽连接信息的配置与上⾯是类似的,只不过在连接池特有属性上,⽅式略有不同:

    <span style="background-color:#f8f8f8"><span style="color:#0000ff">spring.datasource.druid.driver-class-name</span>=<span style="color:#009900">com.mysql.cj.jdbc.Driver</span>
    <span style="color:#0000ff">spring.datasource.druid.url</span>=<span style="color:#009900">jdbc</span>:<span style="color:#009900">mysql</span>:<span style="color:#009900">//localhost</span>:<span style="color:#009900">3306/test?serverTimezone</span>=<span style="color:#009900">UTC</span>
    <span style="color:#0000ff">spring.datasource.druid.username</span>=<span style="color:#009900">root</span>
    <span style="color:#0000ff">spring.datasource.druid.password</span>=<span style="color:#009900">123456</span>
    ​
    <span style="color:#aa5500">#初始化连接数</span>
    <span style="color:#0000ff">spring.datasource.initial-size</span>=<span style="color:#009900">1 #最⼩空闲连接</span>
    <span style="color:#0000ff">spring.datasource.min-idle</span>=<span style="color:#009900">1 #最⼤活动连接</span>
    <span style="color:#0000ff">spring.datasource.max-active</span>=<span style="color:#009900">20</span>
    <span style="color:#aa5500">#获取连接时测试是否可⽤</span>
    <span style="color:#0000ff">spring.datasource.test-on-borrow</span>=<span style="color:#009900">true</span></span>

3、SpringBoot整合事务

1,事务的概念

其实,我们引⼊jdbc或者web的启动器,就已经引⼊事务相关的依赖及默认配置了

 

⾄于事务,SpringBoot中通过注解来控制。就是我们熟知的 @Transactional

  • @Transactional 注解默认会回滚运行时异常及其子类

     

  • @Transactional 注解只能应用到 public 方法或者类上才有效

  • 注意:如果异常被try{}catch{}了,事务就不回滚了,如果想让事务回滚必须再往外抛try{}catch(Exception e){throw e}。

二、SpringBoot单元测试

1、引入启动器

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#117700"><</span><span style="color:#117700">dependency</span><span style="color:#117700">></span>
    <span style="color:#117700"><</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>org.springframework.boot<span style="color:#117700"></</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>
    <span style="color:#117700"><</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>spring-boot-starter-test<span style="color:#117700"></</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>
<span style="color:#117700"></</span><span style="color:#117700">dependency</span><span style="color:#117700">></span></span></span>

2、测试方式1

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#770088">import</span> <span style="color:#000000">org</span>.<span style="color:#000000">junit</span>.<span style="color:#000000">Test</span>;
​
<span style="color:#555555">@RunWith</span>(<span style="color:#000000">SpringJUnit4ClassRunner</span>.<span style="color:#770088">class</span>)
<span style="color:#555555">@SpringBootTest</span>(<span style="color:#000000">classes</span> <span style="color:#981a1a">=</span> {<span style="color:#000000">ApplicationApp</span>.<span style="color:#770088">class</span>})
<span style="color:#770088">public</span> <span style="color:#770088">class</span> <span style="color:#0000ff">MyTest</span> {
​
    <span style="color:#555555">@Autowired</span>
    <span style="color:#770088">private</span> <span style="color:#000000">IUserService</span> <span style="color:#000000">userService</span>;
​
    <span style="color:#555555">@Test</span>
    <span style="color:#770088">public</span> <span style="color:#008855">void</span> <span style="color:#000000">userTest</span>(){
        <span style="color:#000000">System</span>.<span style="color:#000000">out</span>.<span style="color:#000000">println</span>(<span style="color:#000000">userService</span>.<span style="color:#000000">findUser</span>());
    }
}</span></span>

3、测试方式2

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#770088">import</span> <span style="color:#000000">org</span>.<span style="color:#000000">junit</span>.<span style="color:#000000">jupiter</span>.<span style="color:#000000">api</span>.<span style="color:#000000">Test</span>;  <span style="color:#aa5500">//注意junit包名</span>
​
<span style="color:#555555">@SpringBootTest</span>(<span style="color:#000000">classes</span> <span style="color:#981a1a">=</span> <span style="color:#000000">ApplicationApp</span>.<span style="color:#770088">class</span>)
<span style="color:#770088">public</span> <span style="color:#770088">class</span> <span style="color:#0000ff">MyTest</span> {
​
    <span style="color:#555555">@Autowired</span>
    <span style="color:#770088">private</span> <span style="color:#000000">IUserService</span> <span style="color:#000000">userService</span>;
​
    <span style="color:#555555">@Test</span>
    <span style="color:#770088">public</span> <span style="color:#008855">void</span> <span style="color:#000000">userTest</span>(){
        <span style="color:#000000">System</span>.<span style="color:#000000">out</span>.<span style="color:#000000">println</span>(<span style="color:#000000">userService</span>.<span style="color:#000000">findUser</span>());
    }
}</span></span>

三、SpringBoot整合MVC

1、访问静态资源

现在,我们的项⽬是⼀个jar⼯程,那么就没有webapp,我们的静态资源该放哪⾥呢?回顾我们上⾯看的源码,有⼀个叫做ResourceProperties的类继承的Resources类,⾥⾯就定义了静态资源的默认查找路径

 

默认的静态资源路径为:

  • classpath:/META-INF/resources/

  • classpath:/resources/

  • classpath:/static/

  • classpath:/public/

只要静态资源放在这些⽬录中任何⼀个,SpringMVC都会帮我们处理

我们习惯会把静态资源放在 classpath:/static/ ⽬录下。我们创建⽬录,并且添加⼀些静态资源:

   重启项⽬后测试:

locahost:8080/项⽬名/css/index.css

locahost:8080/项⽬名/js/index.js

locahost:8080/项⽬名/images/01.png

当然我们也可以放到⾃⼰新建的⽂件夹中,如下图

 

然后在springboot的全局配置⽂件中,让它默认也去my路径下查找即可

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#0000ff">spring.web.resources.static-locations</span>=<span style="color:#009900">classpath</span>:<span style="color:#009900">/META-INF/resources/,classpath</span>:<span style="color:#009900">/resources/,classpath</span>:<span style="color:#009900">/static/,classpath</span>:<span style="color:#009900">/public/,classpath</span>:<span style="color:#009900">/my/</span></span></span>

四、SpringBoot异常处理

1、默认方式

SpringBoot 默认的处理异常的机制:SpringBoot 默认的已经提供了一套处理异常的机制。一旦程序中出现了异常 SpringBoot 向src/main/resources/templates目录下的/error 的 url 发送请求。在 springBoot 中提供了一个叫 BasicErrorController 来处理/error 请求,然后跳转到默认显示异常的页面来展示异常信息。

在pom.xml 引入thymeleaf依赖

<span style="background-color:#f8f8f8"><span style="color:#333333">   <span style="color:#117700"><</span><span style="color:#117700">dependency</span><span style="color:#117700">></span>
            <span style="color:#117700"><</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>org.springframework.boot<span style="color:#117700"></</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>
            <span style="color:#117700"><</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>spring-boot-starter-thymeleaf<span style="color:#117700"></</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>
   <span style="color:#117700"></</span><span style="color:#117700">dependency</span><span style="color:#117700">></span></span></span>

  • 在src/main/resources/ templates创建error.html页面

    <span style="background-color:#f8f8f8"><span style="color:#555555"><!DOCTYPE html></span>
    <span style="color:#117700"><</span><span style="color:#117700">html</span> <span style="color:#0000cc">xmlns:th</span>=<span style="color:#aa1111">"http://www.thymeleaf.org"</span><span style="color:#117700">></span>
    <span style="color:#117700"><</span><span style="color:#117700">head</span><span style="color:#117700">></span>
        <span style="color:#117700"><</span><span style="color:#117700">meta</span> <span style="color:#0000cc">charset</span>=<span style="color:#aa1111">"UTF-8"</span><span style="color:#117700">></span>
        <span style="color:#117700"><</span><span style="color:#117700">title</span><span style="color:#117700">></span>错误提示页面<span style="color:#117700"></</span><span style="color:#117700">title</span><span style="color:#117700">></span>
    <span style="color:#117700"></</span><span style="color:#117700">head</span><span style="color:#117700">></span>
    <span style="color:#117700"><</span><span style="color:#117700">body</span><span style="color:#117700">></span>
    出错了,请与管理员联系。。。
    <span style="color:#117700"></</span><span style="color:#117700">body</span><span style="color:#117700">></span>
    <span style="color:#117700"></</span><span style="color:#117700">html</span><span style="color:#117700">></span></span>
  • 修改controller

    <span style="background-color:#f8f8f8"><span style="color:#555555">@Controller</span>
    <span style="color:#770088">public</span> <span style="color:#770088">class</span> <span style="color:#0000ff">HelloController</span> {
        <span style="color:#555555">@RequestMapping</span>(<span style="color:#aa1111">"show"</span>)
        <span style="color:#770088">public</span> <span style="color:#008855">String</span> <span style="color:#000000">showInfo</span>(){
           <span style="color:#008855">int</span> <span style="color:#000000">i</span><span style="color:#981a1a">=</span><span style="color:#116644">1</span><span style="color:#981a1a">/</span><span style="color:#116644">0</span>;
            <span style="color:#770088">return</span> <span style="color:#aa1111">"index"</span>;
        }
    }</span>

    当我们在浏览器访问http://localhost/show时,会报异常,此时直接跳转到error.html页面

2、@ExceptionHandle 注解方式

在controller当前类中添加方法来捕获当前类抛出的异常,从而进行处理,该方法上添加@ExceptionHandler注解

  • 在resources/templates目录下创建error1.html页面

    <span style="background-color:#f8f8f8"><span style="color:#555555"><!DOCTYPE html></span>
    <span style="color:#117700"><</span><span style="color:#117700">html</span> <span style="color:#0000cc">xmlns:th</span>=<span style="color:#aa1111">"http://www.thymeleaf.org"</span><span style="color:#117700">></span>
    <span style="color:#117700"><</span><span style="color:#117700">head</span><span style="color:#117700">></span>
        <span style="color:#117700"><</span><span style="color:#117700">meta</span> <span style="color:#0000cc">charset</span>=<span style="color:#aa1111">"UTF-8"</span><span style="color:#117700">></span>
        <span style="color:#117700"><</span><span style="color:#117700">title</span><span style="color:#117700">></span>错误提示页面-ArithmeticException<span style="color:#117700"></</span><span style="color:#117700">title</span><span style="color:#117700">></span>
    <span style="color:#117700"></</span><span style="color:#117700">head</span><span style="color:#117700">></span>
    <span style="color:#117700"><</span><span style="color:#117700">body</span><span style="color:#117700">></span>
        出错了,请与管理员联系。。。
        <span style="color:#117700"><</span><span style="color:#117700">span</span> <span style="color:#0000cc">th:text</span>=<span style="color:#aa1111">"${error}"</span><span style="color:#117700">></</span><span style="color:#117700">span</span><span style="color:#117700">></span>
    <span style="color:#117700"></</span><span style="color:#117700">body</span><span style="color:#117700">></span>
    <span style="color:#117700"></</span><span style="color:#117700">html</span><span style="color:#117700">></span></span>
  • 修改controller

    <span style="background-color:#f8f8f8"><span style="color:#555555">@Controller</span>
    <span style="color:#770088">public</span> <span style="color:#770088">class</span> <span style="color:#0000ff">HelloController</span> {
        <span style="color:#555555">@RequestMapping</span>(<span style="color:#aa1111">"show"</span>)
        <span style="color:#770088">public</span> <span style="color:#008855">String</span> <span style="color:#000000">showInfo</span>(){
           <span style="color:#008855">int</span> <span style="color:#000000">i</span><span style="color:#981a1a">=</span><span style="color:#116644">1</span><span style="color:#981a1a">/</span><span style="color:#116644">0</span>;
            <span style="color:#770088">return</span> <span style="color:#aa1111">"index"</span>;
        }
    ​
        <span style="color:#aa5500">/**</span>
         <span style="color:#aa5500">* 异常处理方法</span>
         <span style="color:#aa5500">* @param e</span>
         <span style="color:#aa5500">* @return</span>
         <span style="color:#aa5500">*/</span>
        <span style="color:#555555">@ExceptionHandler</span>(<span style="color:#000000">value</span> <span style="color:#981a1a">=</span> {<span style="color:#000000">java</span>.<span style="color:#000000">lang</span>.<span style="color:#000000">ArithmeticException</span>.<span style="color:#770088">class</span>})
        <span style="color:#770088">public</span> <span style="color:#000000">ModelAndView</span> <span style="color:#000000">arithmeticExceptionHandler</span>(<span style="color:#000000">Exception</span> <span style="color:#000000">e</span>) {
            <span style="color:#000000">ModelAndView</span> <span style="color:#000000">model</span> <span style="color:#981a1a">=</span> <span style="color:#770088">new</span> <span style="color:#000000">ModelAndView</span>();
            <span style="color:#000000">model</span>.<span style="color:#000000">addObject</span>(<span style="color:#aa1111">"error"</span>, <span style="color:#000000">e</span>.<span style="color:#000000">toString</span>());
            <span style="color:#000000">model</span>.<span style="color:#000000">setViewName</span>(<span style="color:#aa1111">"error1"</span>);  <span style="color:#aa5500">//逻辑视图名</span>
            <span style="color:#770088">return</span> <span style="color:#000000">model</span>;
        }
    }</span>

3、@ControllerAdvice方式

自定义一个类GlobalException,并添加注解 @ControllerAdvice,或者@RestControllerAdvice, 在处理异常的方法上面添加@ExceptionHandler注解并在value中添加要处理的异常

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#555555">@ControllerAdvice</span>
<span style="color:#770088">public</span> <span style="color:#770088">class</span> <span style="color:#0000ff">GlobalException</span> {
    <span style="color:#aa5500">/**</span>
     <span style="color:#aa5500">* java.lang.ArithmeticException</span>
     <span style="color:#aa5500">* 该方法需要返回一个 ModelAndView:目的是可以让我们封装异常信息以及视</span>
     <span style="color:#aa5500">* 图的指定</span>
     <span style="color:#aa5500">* 参数 Exception e:会将产生异常对象注入到方法中</span>
     <span style="color:#aa5500">*/</span>
    <span style="color:#555555">@ExceptionHandler</span>(<span style="color:#000000">value</span> <span style="color:#981a1a">=</span> {<span style="color:#000000">ArithmeticException</span>.<span style="color:#770088">class</span>})
    <span style="color:#770088">public</span> <span style="color:#000000">ModelAndView</span> <span style="color:#000000">arithmeticExceptionHandler</span>(<span style="color:#000000">Exception</span> <span style="color:#000000">e</span>) {
        <span style="color:#000000">ModelAndView</span> <span style="color:#000000">mv</span> <span style="color:#981a1a">=</span> <span style="color:#770088">new</span> <span style="color:#000000">ModelAndView</span>();
        <span style="color:#000000">mv</span>.<span style="color:#000000">addObject</span>(<span style="color:#aa1111">"error"</span>, <span style="color:#000000">e</span>.<span style="color:#000000">toString</span>());
        <span style="color:#000000">mv</span>.<span style="color:#000000">setViewName</span>(<span style="color:#aa1111">"error"</span>);
        <span style="color:#770088">return</span> <span style="color:#000000">mv</span>;
    }
​
    <span style="color:#aa5500">/**</span>
     <span style="color:#aa5500">* java.lang.NullPointerException</span>
     <span style="color:#aa5500">* 该方法需要返回一个 ModelAndView:目的是可以让我们封装异常信息以及视</span>
     <span style="color:#aa5500">* 图的指定</span>
     <span style="color:#aa5500">* 参数 Exception e:会将产生异常对象注入到方法中</span>
     <span style="color:#aa5500">*/</span>
    <span style="color:#555555">@ExceptionHandler</span>(<span style="color:#000000">value</span> <span style="color:#981a1a">=</span> {<span style="color:#000000">NullPointerException</span>.<span style="color:#770088">class</span>})
    <span style="color:#770088">public</span> <span style="color:#000000">ModelAndView</span> <span style="color:#000000">nullPointerExceptionHandler</span>(<span style="color:#000000">Exception</span> <span style="color:#000000">e</span>) {
        <span style="color:#000000">ModelAndView</span> <span style="color:#000000">mv</span> <span style="color:#981a1a">=</span> <span style="color:#770088">new</span> <span style="color:#000000">ModelAndView</span>();
        <span style="color:#000000">mv</span>.<span style="color:#000000">addObject</span>(<span style="color:#aa1111">"error"</span>, <span style="color:#000000">e</span>.<span style="color:#000000">toString</span>());
        <span style="color:#000000">mv</span>.<span style="color:#000000">setViewName</span>(<span style="color:#aa1111">"error1"</span>);
        <span style="color:#770088">return</span> <span style="color:#000000">mv</span>;
    }
}</span></span>

五、SpringBoot定时任务

Scheduled 定时任务器:是 Spring3.0 以后自带的一个定时任务器

1、 引入依赖

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#117700"><</span><span style="color:#117700">dependency</span><span style="color:#117700">></span>
    <span style="color:#117700"><</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>org.springframework.boot<span style="color:#117700"></</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>
    <span style="color:#117700"><</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>spring-boot-starter-web<span style="color:#117700"></</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>
<span style="color:#117700"></</span><span style="color:#117700">dependency</span><span style="color:#117700">></span></span></span>

2、编写定时任务

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#555555">@Component</span>
<span style="color:#770088">public</span> <span style="color:#770088">class</span> <span style="color:#0000ff">ScheduledDemo</span> {
    <span style="color:#aa5500">/**</span>
     <span style="color:#aa5500">*定时任务方法</span>
     <span style="color:#aa5500">* @Scheduled:设置定时任务 cron 属性:cron 表达式。定时任务触发是时间的一个字符串表达形式</span>
     <span style="color:#aa5500">*/</span>
    <span style="color:#555555">@Scheduled</span>(<span style="color:#000000">cron</span> <span style="color:#981a1a">=</span> <span style="color:#aa1111">"0/2 * * * * ?"</span>)
    <span style="color:#aa5500">//@Scheduled(initialDelay =  1000 * 10,fixedRate = 1000 * 5) //fixedRate = 1000 *5表示每5秒执行一次</span>
    <span style="color:#770088">public</span> <span style="color:#008855">void</span> <span style="color:#000000">scheduledMethod</span>() {
        <span style="color:#000000">System</span>.<span style="color:#000000">out</span>.<span style="color:#000000">println</span>(<span style="color:#aa1111">"定时器被触发"</span> <span style="color:#981a1a">+</span> <span style="color:#770088">new</span> <span style="color:#000000">Date</span>());
    }
}</span></span>

3、 开启定时任务注解

在启动类中添加@EnableScheduling注解

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#aa5500">/**</span>
 <span style="color:#aa5500">* 启动类</span>
 <span style="color:#aa5500">*/</span>
<span style="color:#555555">@SpringBootApplication</span>
<span style="color:#555555">@MapperScan</span>(<span style="color:#aa1111">"cn.woniu.dao"</span>)<span style="color:#aa5500">//扫描dao</span>
<span style="color:#555555">@EnableScheduling</span> <span style="color:#aa5500">//开启定时任务</span>
<span style="color:#770088">public</span> <span style="color:#770088">class</span> <span style="color:#0000ff">ApplicationApp</span> {
    <span style="color:#770088">public</span> <span style="color:#770088">static</span> <span style="color:#008855">void</span> <span style="color:#000000">main</span>(<span style="color:#008855">String</span>[] <span style="color:#000000">args</span>) {
        <span style="color:#000000">SpringApplication</span>.<span style="color:#000000">run</span>(<span style="color:#000000">ApplicationApp</span>.<span style="color:#770088">class</span>,<span style="color:#000000">args</span>);
    }
}</span></span>

4、Cron 表达式

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#0000ff">Cron 表达式是一个字符串,分为 6 或 7 个域,每一个域代表一个含义;</span>
<span style="color:#0000ff">Cron 从左到右(用空格隔开): 秒   分   小时   月份中的日期   月份   星期中的日期    年份(可省略)</span></span></span>

Cron 有如下两种语法格式:

  • Seconds Minutes Hours Day Month Week Year

  • Seconds Minutes Hours Day Month Week

序号说明取值表达式
10-59-*/
2分钟0-59-*/
3小时0-23-*/
41-31-*/LWC
51-12-*/
6星期1-7-*?/LC#
7年(可选)1970-2099-*/

Cron 表达式的时间字段除允许设置数值外,还可使用一些特殊的字符,提供列表、范围、通配符等功,如下:

  • 星号(*):可用在所有字段中,表示对应时间域的每一个时刻,例如,在分钟字段时,表示“每分钟”;

  • 问号(?):该字符只在日期和星期字段中使用,它通常指定为“无意义的值”,相当于占位符;

  • 减号(-):表达一个范围,如在小时字段中使用“10-12”,则表示从 10 到 12 点,即 10,11,12;

  • 逗号(,):表达一个列表值,如在星期字段中使用“MON,WED,FRI”,则表示星期一,星期三和星期五;

  • 斜杠(/):x/y 表达一个等步长序列,x 为起始值,y 为增量步长值。如在分钟字段中使用 0/15,则表示为 0,15,30 和 45 秒,而 5/15 在分钟字段中表示 5,20,35,50,你也可以使用*/y,它等同于 0/y;

  • L:该字符只在日期和星期字段中使用,代表“Last”的意思,但它在两个字段中意思不同。L 在日期字段中,表示这个月份的最后一天,如一月的 31 号,非闰年二月的 28 号;如果 L 用在星期中,则表示星期六,等同于 7。但是,如果 L 出现在星期字段里,而且在前面有一个数值 X,则表示“这个月的最后 X 天”,例如,6L 表示该月的最后星期五;

  • W:该字符只能出现在日期字段里,是对前导日期的修饰,表示离该日期最近的工作日。例如 15W表示离该月 15 号最近的工作日,如果该月 15 号是星期六,则匹配 14 号星期五;如果 15 日是星期日,则匹配 16 号星期一;如果 15 号是星期二,那结果就是 15 号星期二。但必须注意关联的匹配日期不能够跨月,如你指定 1W,如果 1 号是星期六,结果匹配的是 3 号星期一,而非上个月最后的那天。W 字符串只能指定单一日期,而不能指定日期范围;

  • LW 组合:在日期字段可以组合使用 LW,它的意思是当月的最后一个工作日;

  • 井号(#):该字符只能在星期字段中使用,表示当月某个工作日。如 6#3 表示当月的第三个星期五(6表示星期五,#3 表示当前的第三个),而 4#5 表示当月的第五个星期三,假设当月没有第五个星期三,忽略不触发;

  • C:该字符只在日期和星期字段中使用,代表“Calendar”的意思。它的意思是计划所关联的日期,如果日期没有被关联,则相当于日历中所有日期。例如 5C 在日期字段中就相当于日历 5 日以后的第一天。1C 在星期字段中相当于星期日后的第一天。

案例说明:

<span style="background-color:#f8f8f8"><span style="color:#333333"><span style="color:#0000ff">@Scheduled(cron </span>=<span style="color:#009900"> "0 0 1 1 1 ?")//每年一月的一号的 1</span>:<span style="color:#009900">00</span>:<span style="color:#009900">00 执行一次</span>
<span style="color:#0000ff">@Scheduled(cron </span>=<span style="color:#009900"> "0 0 1 1 1,6 ?") //一月和六月的一号的 1</span>:<span style="color:#009900">00</span>:<span style="color:#009900">00 执行一次</span>
<span style="color:#0000ff">@Scheduled(cron </span>=<span style="color:#009900"> "0 0 1 1 1,4,7,10 ?") //每个季度的第一个月的一号的 1</span>:<span style="color:#009900">00</span>:<span style="color:#009900">00 执行一次</span>
<span style="color:#0000ff">@Scheduled(cron </span>=<span style="color:#009900"> "0 0 1 1 * ?")//每月一号 1</span>:<span style="color:#009900">00</span>:<span style="color:#009900">00 执行一次</span>
<span style="color:#0000ff">@Scheduled(cron</span>=<span style="color:#009900">"0 0 1 * * *") //每天凌晨 1 点执行一次</span></span></span>

六,打包

1、打jar包

  • 修改pom将找包方式改为jar

    <span style="background-color:#f8f8f8"><span style="color:#117700"><</span><span style="color:#117700">packaging</span><span style="color:#117700">></span>jar<span style="color:#117700"></</span><span style="color:#117700">packaging</span><span style="color:#117700">></span></span>
  • 在工程中添加插件

<span style="background-color:#f8f8f8"><span style="color:#333333">   <span style="color:#117700"><</span><span style="color:#117700">build</span><span style="color:#117700">></span>
        <span style="color:#117700"><</span><span style="color:#117700">plugins</span><span style="color:#117700">></span>
            <span style="color:#117700"><</span><span style="color:#117700">plugin</span><span style="color:#117700">></span>
                <span style="color:#117700"><</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>org.springframework.boot<span style="color:#117700"></</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>
                <span style="color:#117700"><</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>spring-boot-maven-plugin<span style="color:#117700"></</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>
            <span style="color:#117700"></</span><span style="color:#117700">plugin</span><span style="color:#117700">></span>
            <span style="color:#117700"><</span><span style="color:#117700">plugin</span><span style="color:#117700">></span>
                <span style="color:#117700"><</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>org.apache.maven.plugins<span style="color:#117700"></</span><span style="color:#117700">groupId</span><span style="color:#117700">></span>
                <span style="color:#117700"><</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>maven-resources-plugin<span style="color:#117700"></</span><span style="color:#117700">artifactId</span><span style="color:#117700">></span>
                <span style="color:#117700"><</span><span style="color:#117700">version</span><span style="color:#117700">></span>3.0.2<span style="color:#117700"></</span><span style="color:#117700">version</span><span style="color:#117700">></span>
            <span style="color:#117700"></</span><span style="color:#117700">plugin</span><span style="color:#117700">></span>
        <span style="color:#117700"></</span><span style="color:#117700">plugins</span><span style="color:#117700">></span>
    <span style="color:#117700"></</span><span style="color:#117700">build</span><span style="color:#117700">></span></span></span>
  • 执行package命令

     

打包之后,在target⽬录下⽣成jar⽂件。进⼊该⽬录,然后在命令⾏窗⼝执⾏

java -jar 包名

注意:如果是⼀个web⼯程也是可以打成jar包的

在cmd中输入: java -jar 生成的jar包名称.jar  运行项目

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