下载mysql驱动和mybatis-generator相关包
需要下载mysql驱动和mybatis-generator-core包。可以使用gradle或maven等插件下载或直接去官网下载。本文以gradle为例。
在build.gradle中添加依赖
/*mysql驱动*/
compile 'mysql:mysql-connector-java:5.1.34'
/*mybatis 自动生成插件*/
compile 'org.mybatis.generator:mybatis-generator-core:1.3.5'
在项目中增加配置文件：generatorConfig.xml
反向生成java文件，需要一个配置文件，配置数据库的连接，生成代码的位置等信息。
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
"http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
<context id="DB2Tables" targetRuntime="MyBatis3">
<!-- 定义如何连接目标数据库 -->
<jdbcConnection driverClass="${jdbc.driverClassName}" connectionURL="${jdbc.url}"
userId="${jdbc.username}" password="${jdbc.password}">
</jdbcConnection>
<javaTypeResolver >
<property name="forceBigDecimals" value="false" />
</javaTypeResolver>
<!-- 指定生成 Java 模型对象所属的包 -->
<javaModelGenerator targetPackage="com.ai.emall.bean.gbean" targetProject="src\main\generate">
<property name="enableSubPackages" value="false" />
<property name="trimStrings" value="true" />
</javaModelGenerator>
<!-- 指定生成 SQL 映射文件所属的包和的目标项目 -->
<sqlMapGenerator targetPackage="mybatis.gmapper" targetProject="src\main\resources">
<property name="enableSubPackages" value="false" />
</sqlMapGenerator>
<!-- 指定目标包和目标项目生成的客户端接口和类 -->
<javaClientGenerator type="XMLMAPPER" targetPackage="com.ai.emall.dao.gdao" targetProject="src\main\generate">
<property name="enableSubPackages" value="true" />
</javaClientGenerator>
<!-- 设置要生成的表名 -->
<table tableName="product" >
</table>
</context>
</generatorConfiguration>
创建Main方法，生成相关代码
/**
* 生成mybaits相关mapper,bean,dao等
* @author ZWG
*
*/
public class MybatisGenerateRun {
public static void main(String[] args) throws IOException, XMLParserException, InvalidConfigurationException, SQLException, InterruptedException {
List<String> warnings = new ArrayList<String>();
boolean overwrite = true;
//加载generatorEmallConfig文件
File configFile = new File(MybatisGenerateRun.class.getClassLoader().getResource("generatorConfig.xml").getPath());
//加载数据库信息，例如driverClassName，username,password,url等
Properties extraProperties = PropertiesLoaderUtils.loadAllProperties("mybatis/mybatis-emall.properties");
ConfigurationParser cp = new ConfigurationParser(extraProperties, warnings);
Configuration config = cp.parseConfiguration(configFile);
DefaultShellCallback callback = new DefaultShellCallback(overwrite);
MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
myBatisGenerator.generate(null);
if(!CollectionUtils.isEmpty(warnings)){
for (String warn : warnings) {
System.out.println(warn);
}
}
System.out.println("生成成功！");
}
}
运行main方法，生成成功
mybatisGenerate.png
自定义生成的注释
通过上面生成的bean文件，每个字段会生成相应的注释，生成的注释如下:
public class Product {
/**
*
* This field was generated by MyBatis Generator.
* This field corresponds to the database column product.PRODUCT_ID
*
* @mbg.generated Tue Jan 10 19:45:10 CST 2017
*/
private Long productId;
/**
* This method was generated by MyBatis Generator.
* This method returns the value of the database column product.PRODUCT_ID
*
* @return the value of product.PRODUCT_ID
*
* @mbg.generated Tue Jan 10 19:45:10 CST 2017
*/
public Long getProductId() {
return productId;
}
/**
* This method was generated by MyBatis Generator.
* This method sets the value of the database column product.PRODUCT_ID
*
* @param productId the value for product.PRODUCT_ID
*
* @mbg.generated Tue Jan 10 19:45:10 CST 2017
*/
public void setProductId(Long productId) {
this.productId = productId;
}
}
可以看到这并不是我们想要的注释，如果我们想生成数据库中的注释，可以使用Mybatis提供的CommentGenerator接口，具体步骤如下：
1. 创建自定义注释生成类，需要继承CommentGenerator接口
/**
* 自定义Mybatis注释 使用数据库中的注释
* @author ZWG
*
*/
public class MybatisGeneratorCommon implements CommentGenerator{
@Override
public void addConfigurationProperties(Properties properties) {}
@Override
public void addFieldComment(Field field, IntrospectedTable introspectedTable,
IntrospectedColumn introspectedColumn) {
//判断数据库中该字段注释是否为空
if(StringUtils.isEmpty(introspectedColumn.getRemarks()))
return;
field.addJavaDocLine("/**"+introspectedColumn.getRemarks()+"*/");
}
@Override
public void addFieldComment(Field field, IntrospectedTable introspectedTable) {}
@Override
public void addModelClassComment(TopLevelClass topLevelClass, IntrospectedTable introspectedTable) {}
@Override
public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable) {}
@Override
public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable, boolean markAsDoNotDelete) {}
@Override
public void addEnumComment(InnerEnum innerEnum, IntrospectedTable introspectedTable) {}
@Override
public void addGetterComment(Method method, IntrospectedTable introspectedTable,
IntrospectedColumn introspectedColumn) {
if(StringUtils.isEmpty(introspectedColumn.getRemarks()))
return;
method.addJavaDocLine("/**获取"+introspectedColumn.getRemarks()+"*/");
}
@Override
public void addSetterComment(Method method, IntrospectedTable introspectedTable,
IntrospectedColumn introspectedColumn) {
if(StringUtils.isEmpty(introspectedColumn.getRemarks()))
return;
method.addJavaDocLine("/**设置"+introspectedColumn.getRemarks()+"*/");
}
@Override
public void addGeneralMethodComment(Method method, IntrospectedTable introspectedTable) {}
@Override
public void addJavaFileComment(CompilationUnit compilationUnit) {}
@Override
public void addComment(XmlElement xmlElement) {}
@Override
public void addRootComment(XmlElement rootElement) {}
}
1. 将自定义的注释类添加到配置中。
在上面generatorConfig.xml中的context元素中增加如下信息:
<!-- 自定义注释生成器 MybatisGeneratorCommon类为我自定义的继承CommentGenerator的类 -->
<commentGenerator type="com.ai.emall.util.MybatisGeneratorCommon">
<!-- 关闭自动生成的注释 -->
<property name="suppressAllComments" value="true" />
<property name="suppressDate" value="true" />
</commentGenerator>
注意：generatorConfig.xml中的context下面的元素有严格的顺序关系，上面的commentGenerator需要放到jdbcConnection标签的前面。==
具体顺序为："(property,plugin,commentGenerator?,(connectionFactory|jdbcConnection),javaTypeResolver?,javaModelGenerator,sqlMapGenerator?,javaClientGenerator?,table +)".
使用自定义注释类，生成的bean文件如下：
public class Product {
/**产品ID*/
private Long productId;
/**获取产品ID*/
public Long getProductId() {
return productId;
}
/**设置产品ID*/
public void setProductId(Long productId) {
this.productId = productId;
}
}
参考：
generatorConfig.xml完整的配置文件
mybatis-generator 官网
mybatis-generator用户指南
