目录
一、简介
MyBatis Generator:
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简称MBG，是一个专门为MyBatis框架使用者定制的代码生成器，可以快速的根据表生成对应的映射文件，接口以及bean类。支持基本的增删改查，以及QBC风格的条件查询。但是表连接、存储过程等这些复杂的sql定义需要我们手工编写
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官方文档地址：
http://www.mybatis.org/generator/
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官方工程地址
https://github.com/mybatis/generator/releases
二、使用步骤
1.编写MGB的配置文件
<?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>
<!--
targetRuntime="MyBatis3Simple":生成简单版的CRUD
MyBatis3:豪华版
-->
<context id="DB2Tables" targetRuntime="MyBatis3">
<!-- 指定如何连接到数据库-->
<jdbcConnection driverClass="com.mysql.jdbc.Driver"
connectionURL="jdbc:mysql://localhost:3306/mybatis"
userId="root"
password="123456">
</jdbcConnection>
<javaTypeResolver >
<property name="forceBigDecimals" value="false" />
</javaTypeResolver>
<!-- javaModelGenerator：指定javaBean的生成策略
targetPackage="test.model"：目标包名
targetProject="\MBGTestProject\src"：目标工程
-->
<javaModelGenerator targetPackage="com.itheima.domain" targetProject=".\src">
<property name="enableSubPackages" value="true" />
<property name="trimStrings" value="true" />
</javaModelGenerator>
<!-- sqlMapGenerator：sql映射生成策略： -->
<sqlMapGenerator targetPackage="com.itheima.dao" targetProject=".\src">
<property name="enableSubPackages" value="true" />
</sqlMapGenerator>
<!-- javaClientGenerator:指定mapper接口所在的位置 -->
<javaClientGenerator type="XMLMAPPER" targetPackage="com.itheima.dao" targetProject=".\src">
<property name="enableSubPackages" value="true" />
</javaClientGenerator>
<!-- 指定要逆向分析哪些表：根据表要创建javaBean -->
<table schema="DB2ADMIN" tableName="tb1_employee" domainObjectName="Employee" ></table>
<table schema="DB2ADMIN" tableName="department" domainObjectName="Department" ></table>
</context>
</generatorConfiguration>2.运行代码生成器代码
//如果再次生成，建议将之前生成的数据删除，避免xml向后追加内容问题的出现
List<String> warnings = new ArrayList<String>();
boolean overwrite = true;
File configFile = new File("generatorConfig.xml");
ConfigurationParser cp = new ConfigurationParser(warnings);
Configuration config = cp.parseConfiguration(configFile);
DefaultShellCallback callback = new DefaultShellCallback(overwrite);
MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
myBatisGenerator.generate(null);3.简单测试
private static SqlSessionFactory getSqlSessionFactory() throws IOException {
//1.根据xml配置文件创建一个SqlSessionFactory对象
String resource = "mybatis-config.xml";
InputStream resourceAsStream = Resources.getResourceAsStream(resource);
return new SqlSessionFactoryBuilder().build(resourceAsStream);
}
//查询id为1的员工
@Test
public void test01() throws IOException {
SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
SqlSession sqlSession = sqlSessionFactory.openSession(true);
try {
EmployeeMapper employeeMapper = sqlSession.getMapper(EmployeeMapper.class);
Employee employee = employeeMapper.selectByPrimaryKey(1);
System.out.println(employee);
}finally {
sqlSession.close();
}
}4.QBC风格的带条件查询测试
//查询名字带c或者id为1的员工
@Test
public void test02() throws Exception {
SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
SqlSession sqlSession = sqlSessionFactory.openSession(true);
try {
EmployeeMapper employeeMapper = sqlSession.getMapper(EmployeeMapper.class);
//xxxExample就是封装查询条件的
EmployeeExample employeeExample = new EmployeeExample();
//创建一个Criteria,用来拼装查询条件
EmployeeExample.Criteria criteria = employeeExample.createCriteria();
//查询名字带c的
criteria.andNameLike("%c%");
EmployeeExample.Criteria criteria1 = employeeExample.createCriteria();
//或者id为1的
criteria1.andIdEqualTo(1);
//两个条件用or相连
employeeExample.or(criteria1);
List<Employee> employees = employeeMapper.selectByExample(employeeExample);
for (Employee employee : employees) {
System.out.println(employee);
}
} finally {
sqlSession.close();
}