mysql创建generator字段_Mybatis-generator自动生成代码时候提取数据库的字段注释作为实体类字段、getter/setter方法的注释...

通过上文介绍的方法根据数据库表生成实体类如下所示

image.png

image.png

可以看到默认的英文注释说明了类属性所对应的数据库字段，但是没有拿到数据库中定义的注释。

根据网上找到的资料以及阅读Mybatis-generator源码，发现可以通过自定义注释生成器 CommentGenerator 接口的实现类来达到我们的目的。

通过阅读源码可以看到，代码生成注释是通过DefaultCommentGenerator类实现的，这个类继承了CommentGenerator接口，因此我们可以自己创建一个类继承CommentGenerator接口，然后重写里面相关方法就可以了(可以复制DefaultCommentGenerator中的代码过来，然后修改我们需要改动的方法)。

下面介绍实现过程。

1、自定义一个CommentGenerator接口的实现类，下面是我的自定义实现类代码

package com.xxx.xxx.util.generator;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Properties;

import org.mybatis.generator.api.CommentGenerator;

import org.mybatis.generator.api.IntrospectedColumn;

import org.mybatis.generator.api.IntrospectedTable;

import org.mybatis.generator.api.dom.java.CompilationUnit;

import org.mybatis.generator.api.dom.java.Field;

import org.mybatis.generator.api.dom.java.InnerClass;

import org.mybatis.generator.api.dom.java.InnerEnum;

import org.mybatis.generator.api.dom.java.JavaElement;

import org.mybatis.generator.api.dom.java.Method;

import org.mybatis.generator.api.dom.java.Parameter;

import org.mybatis.generator.api.dom.xml.XmlElement;

import org.mybatis.generator.config.MergeConstants;

import org.mybatis.generator.config.PropertyRegistry;

/**

* 自定义实现 注释生成器 CommentGenerator 接口

* @author 北北

* @date 2018年1月17日上午10:22:11

*/

public class MyCommentGenerator implements CommentGenerator {

private Properties properties;

private Properties systemPro;

private boolean suppressDate;

private boolean suppressAllComments;

private String nowTime;

public MyCommentGenerator() {

super();

properties = new Properties();

systemPro = System.getProperties();

suppressDate = false;

suppressAllComments = false;

nowTime = (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")).format(new Date());

}

public void addJavaFileComment(CompilationUnit compilationUnit) {

if (suppressAllComments) {

return;

}

return;

}

/**

* Adds a suitable comment to warn users that the element was generated, and

* when it was generated.

*/

public void addComment(XmlElement xmlElement) {

return;

}

public void addRootComment(XmlElement rootElement) {

// add no document level comments by default

return;

}

public void addConfigurationProperties(Properties properties) {

this.properties.putAll(properties);

suppressDate = isTrue(properties.getProperty(PropertyRegistry.COMMENT_GENERATOR_SUPPRESS_DATE));

suppressAllComments = isTrue(properties.getProperty(PropertyRegistry.COMMENT_GENERATOR_SUPPRESS_ALL_COMMENTS));

}

/**

* 判断传入参数是否为true

* @author 北北

* @date 2018年2月2日下午3:55:06

* @param property

* @return

*/

private boolean isTrue(String property) {

if("true".equals(property)){

return true;

}

return false;

}

/**

* This method adds the custom javadoc tag for. You may do nothing if you do

* not wish to include the Javadoc tag - however, if you do not include the

* Javadoc tag then the Java merge capability of the eclipse plugin will

* break.

*

* @param javaElement

* the java element

*/

protected void addJavadocTag(JavaElement javaElement, boolean markAsDoNotDelete) {

javaElement.addJavaDocLine(" *");

StringBuilder sb = new StringBuilder();

sb.append(" * ");

sb.append(MergeConstants.NEW_ELEMENT_TAG);

if (markAsDoNotDelete) {

sb.append(" do_not_delete_during_merge");

}

String s = getDateString();

if (s != null) {

sb.append(' ');

sb.append(s);

}

javaElement.addJavaDocLine(sb.toString());

}

/**

* This method returns a formated date string to include in the Javadoc tag

* and XML comments. You may return null if you do not want the date in

* these documentation elements.

*

* @return a string representing the current timestamp, or null

*/

protected String getDateString() {

String result = null;

if (!suppressDate) {

result = nowTime;

}

return result;

}

public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable) {

if (suppressAllComments) {

return;

}

StringBuilder sb = new StringBuilder();

innerClass.addJavaDocLine("/**");

sb.append(" * ");

sb.append(introspectedTable.getFullyQualifiedTable());

sb.append(" ");

sb.append(getDateString());

innerClass.addJavaDocLine(sb.toString().replace("\n", " "));

innerClass.addJavaDocLine(" */");

}

public void addEnumComment(InnerEnum innerEnum, IntrospectedTable introspectedTable) {

if (suppressAllComments) {

return;

}

StringBuilder sb = new StringBuilder();

innerEnum.addJavaDocLine("/**");

sb.append(" * ");

sb.append(introspectedTable.getFullyQualifiedTable());

innerEnum.addJavaDocLine(sb.toString().replace("\n", " "));

innerEnum.addJavaDocLine(" */");

}

/**

* 设置字段注释

*/

public void addFieldComment(Field field, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn) {

if (suppressAllComments) {

return;

}

StringBuilder sb = new StringBuilder();

field.addJavaDocLine("/**");

sb.append(" * ");

sb.append(introspectedColumn.getRemarks() + " " + introspectedColumn.getActualColumnName());

field.addJavaDocLine(sb.toString().replace("\n", " "));

field.addJavaDocLine(" */");

}

public void addFieldComment(Field field, IntrospectedTable introspectedTable) {

if (suppressAllComments) {

return;

}

StringBuilder sb = new StringBuilder();

field.addJavaDocLine("/**");

sb.append(" * ");

sb.append(introspectedTable.getFullyQualifiedTable());

field.addJavaDocLine(sb.toString().replace("\n", " "));

field.addJavaDocLine(" */");

}

public void addGeneralMethodComment(Method method, IntrospectedTable introspectedTable) {

if (suppressAllComments) {

return;

}

method.addJavaDocLine("/**");

addJavadocTag(method, false);

method.addJavaDocLine(" */");

}

/**

* 设置getter方法注释

*/

public void addGetterComment(Method method, IntrospectedTable introspectedTable,

IntrospectedColumn introspectedColumn) {

if (suppressAllComments) {

return;

}

method.addJavaDocLine("/**");

StringBuilder sb = new StringBuilder();

sb.append(" * ");

sb.append(introspectedColumn.getRemarks());

method.addJavaDocLine(sb.toString().replace("\n", " "));

sb.setLength(0);

//加入系统用户

sb.append(" * @author ");

sb.append(systemPro.getProperty("user.name"));

method.addJavaDocLine(sb.toString().replace("\n", " "));

sb.setLength(0);

//是否加入时间戳

if(suppressDate){

sb.append(" * @date " + nowTime);

method.addJavaDocLine(sb.toString().replace("\n", " "));

sb.setLength(0);

}

sb.append(" * @return ");

sb.append(introspectedColumn.getActualColumnName());

sb.append(" ");

sb.append(introspectedColumn.getRemarks());

method.addJavaDocLine(sb.toString().replace("\n", " "));

method.addJavaDocLine(" */");

}

/**

* 设置setter方法注释

*/

public void addSetterComment(Method method, IntrospectedTable introspectedTable,

IntrospectedColumn introspectedColumn) {

if (suppressAllComments) {

return;

}

method.addJavaDocLine("/**");

StringBuilder sb = new StringBuilder();

sb.append(" * ");

sb.append(introspectedColumn.getRemarks());

method.addJavaDocLine(sb.toString().replace("\n", " "));

sb.setLength(0);

//加入系统用户

sb.append(" * @author ");

sb.append(systemPro.getProperty("user.name"));

method.addJavaDocLine(sb.toString().replace("\n", " "));

sb.setLength(0);

//是否加入时间戳

if(suppressDate){

sb.append(" * @date " + nowTime);

method.addJavaDocLine(sb.toString().replace("\n", " "));

sb.setLength(0);

}

Parameter parm = method.getParameters().get(0);

sb.append(" * @param ");

sb.append(parm.getName());

sb.append(" ");

sb.append(introspectedColumn.getRemarks());

method.addJavaDocLine(sb.toString().replace("\n", " "));

method.addJavaDocLine(" */");

}

public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable, boolean markAsDoNotDelete) {

if (suppressAllComments) {

return;

}

StringBuilder sb = new StringBuilder();

innerClass.addJavaDocLine("/**");

sb.append(" * ");

sb.append(introspectedTable.getFullyQualifiedTable());

innerClass.addJavaDocLine(sb.toString().replace("\n", " "));

sb.setLength(0);

sb.append(" * @author ");

sb.append(systemPro.getProperty("user.name"));

sb.append(" ");

sb.append(nowTime);

innerClass.addJavaDocLine(" */");

}

}

2、有了自定义的CommentGenerator实现类之后，我们要使用它，这个也很简单，只需要在配置文件中的myGeneratorConfig.xml中，给commentGenerator元素设置type属性值为我们自定义类的全类名就可以了

3、下图是最终生成实体类的效果

image.png

最后，一般来说我们只需要实现实体类注释的方法就可以，如果觉得要实现CommentGenerator中所有的接口太麻烦的话，也可以让自定义实现类继承DefaultCommentGenerator类，然后重写与实体类属性、getter、setter注释相关的方法就可以了。