MyBatis Generator(MBG)是MyBatis MyBatis 和iBATIS的代码生成器。它将为所有版本的MyBatis以及版本2.2.0之后的iBATIS版本生成代码。它将内省数据库表(或许多表),并将生成可用于访问表的工件。这减少了设置对象和配置文件以与数据库表交互的初始麻烦。MBG寻求对简单CRUD(创建,检索,更新,删除)的大部分数据库操作产生重大影响。您仍然需要为连接查询或存储过程手动编写SQL和对象代码。
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"><< span="">generatorConfiguration> << span="">context id="testTables" targetRuntime="MyBatis3"> << span="">commentGenerator> << span="">property name="suppressAllComments" value="true" /> commentGenerator> << span="">jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://localhost:3306/demo" userId="root" password="12345"> jdbcConnection> << span="">javaTypeResolver> << span="">property name="forceBigDecimals" value="false" /> javaTypeResolver> << span="">javaModelGenerator targetPackage="com.shop.domain" targetProject=".\src"> << span="">property name="enableSubPackages" value="false" /> << span="">property name="trimStrings" value="true" /> javaModelGenerator> << span="">sqlMapGenerator targetPackage="com.shop.mapper" targetProject=".\src"> << span="">property name="enableSubPackages" value="false" /> sqlMapGenerator> << span="">javaClientGenerator type="XMLMAPPER" targetPackage="com.shop.mapper" targetProject=".\src"> << span="">property name="enableSubPackages" value="false" /> javaClientGenerator> << span="">table tableName="order">table> << span="">table tableName="user">table> context>generatorConfiguration> |
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public class Demo1 { @Test public void generator() throws Exception{ Listwarnings = new ArrayList(); boolean overwrite = true; File configFile = new File("generator.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); } public static void main(String[] args) throws Exception { try { Demo1 demo = new Demo1(); demo.generator(); } catch (Exception e) { e.printStackTrace(); }} |
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Mybatis逆向工程注意点:
不要生成多次,否则代码会进行叠加,导致代码出现奇怪的bug
【原因】:
Mapper文件内容不覆盖而是追加
XXXMapper.xml文件已经存在时,如果进行重新生成则mapper.xml文件内容不被覆盖而是进行内容追加,结果导致mybatis解析失败。
解决方法:删除原来已经生成的mapper xml文件再进行生成。
Mybatis自动生成的po及mapper.java文件不是内容而是直接覆盖没有此问题。
//删除符合条件的记录
int deleteByExample(UserExample example);
//根据主键删除
int deleteByPrimaryKey(String id);
//插入对象所有字段
int insert(User record);
//插入对象不为空的字段
int insertSelective(User record);
//自定义查询条件查询结果集
ListselectByExample(UserExample example);
//根据主键查询
UserselectByPrimaryKey(String id);
//根据主键将对象中不为空的值更新至数据库
int updateByPrimaryKeySelective(User record);
//根据主键将对象中所有字段的值更新至数据库
int updateByPrimaryKey(User record);
public class Demo1 { @Test public void fun1() throws IOException { // 读取mybatis的核心配置文件 String configXml = "mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(configXml); // 创建sqlSessionFactory SqlSessionFactory sqlSession = new SqlSessionFactoryBuilder().build(inputStream); // 使用sqlSessionFactory 创建sqlSession SqlSession session = sqlSession.openSession(); UserMapper userMapper = session.getMapper(UserMapper.class); User user = userMapper.selectByPrimaryKey(1); System.out.println(user); } @Test public void fun2() throws IOException { // 读取mybatis的核心配置文件 String configXml = "mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(configXml); // 创建sqlSessionFactory SqlSessionFactory sqlSession = new SqlSessionFactoryBuilder().build(inputStream); // 使用sqlSessionFactory 创建sqlSession SqlSession session = sqlSession.openSession(); UserMapper userMapper = session.getMapper(UserMapper.class); UserExample example = new UserExample(); Criteria criteria = example.createCriteria(); criteria.andUsernameLike("%陈%"); criteria.andSexEqualTo("1"); Listlist = userMapper.selectByExample(example); for (User user : list) { System.out.println(user); } }} |
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