使用MyBatis对表执行增删改查操作——基于注解的实现

上篇博文的基于xml配置的只要学会了，原理搞清楚了，那么注解的方式更是随意学会，因为注解就是为了简化配置，甚至是不需要xml文件配置的。

下面是装载别人的一个注解项目，可以参考改动：

1、定义sql映射的接口

    package me.gacl.mapping;            import java.util.List;      import me.gacl.domain.User;      import org.apache.ibatis.annotations.Delete;      import org.apache.ibatis.annotations.Insert;      import org.apache.ibatis.annotations.Select;      import org.apache.ibatis.annotations.Update;            /**      * @author gacl      * 定义sql映射的接口，使用注解指明方法要执行的SQL      */      public interface UserMapperI {                //使用@Insert注解指明add方法要执行的SQL          @Insert("insert into users(name, age) values(#{name}, #{age})")          public int add(User user);                    //使用@Delete注解指明deleteById方法要执行的SQL          @Delete("delete from users where id=#{id}")          public int deleteById(int id);                    //使用@Update注解指明update方法要执行的SQL          @Update("update users set name=#{name},age=#{age} where id=#{id}")          public int update(User user);                    //使用@Select注解指明getById方法要执行的SQL          @Select("select * from users where id=#{id}")          public User getById(int id);                    //使用@Select注解指明getAll方法要执行的SQL          @Select("select * from users")          public List<User> getAll();      }  

2、在conf.xml文件注册映射接口

    <?xml version="1.0" encoding="UTF-8"?>      <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">      <configuration>          <environments default="development">              <environment id="development">                  <transactionManager type="JDBC" />                  <!-- 配置数据库连接信息 -->                  <dataSource type="POOLED">                      <property name="driver" value="com.mysql.jdbc.Driver" />                      <property name="url" value="jdbc:mysql://localhost:3306/mybatis" />                      <property name="username" value="root" />                      <property name="password" value="XDP" />                  </dataSource>              </environment>          </environments>                    <mappers>              <!-- 注册userMapper.xml文件，               userMapper.xml位于me.gacl.mapping这个包下，所以resource写成me/gacl/mapping/userMapper.xml-->              <mapper resource="me/gacl/mapping/userMapper.xml"/>              <!-- 注册UserMapper映射接口-->              <mapper class="me.gacl.mapping.UserMapperI"/>          </mappers>                </configuration>  

3.测试类方法：

    package me.gacl.test;            import java.util.List;      import me.gacl.domain.User;      import me.gacl.mapping.UserMapperI;      import me.gacl.util.MyBatisUtil;      import org.apache.ibatis.session.SqlSession;      import org.junit.Test;            public class TestCRUDByAnnotationMapper {                @Test          public void testAdd(){              SqlSession sqlSession = MyBatisUtil.getSqlSession(true);              //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来              UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);              User user = new User();              user.setName("用户xdp");              user.setAge(20);              int add = mapper.add(user);              //使用SqlSession执行完SQL之后需要关闭SqlSession              sqlSession.close();              System.out.println(add);          }                    @Test          public void testUpdate(){              SqlSession sqlSession = MyBatisUtil.getSqlSession(true);              //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来              UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);              User user = new User();              user.setId(3);              user.setName("孤傲苍狼_xdp");              user.setAge(26);              //执行修改操作              int retResult = mapper.update(user);              //使用SqlSession执行完SQL之后需要关闭SqlSession              sqlSession.close();              System.out.println(retResult);          }                    @Test          public void testDelete(){              SqlSession sqlSession = MyBatisUtil.getSqlSession(true);              //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来              UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);              //执行删除操作              int retResult = mapper.deleteById(7);              //使用SqlSession执行完SQL之后需要关闭SqlSession              sqlSession.close();              System.out.println(retResult);          }                    @Test          public void testGetUser(){              SqlSession sqlSession = MyBatisUtil.getSqlSession();              //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来              UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);              //执行查询操作，将查询结果自动封装成User返回              User user = mapper.getById(8);              //使用SqlSession执行完SQL之后需要关闭SqlSession              sqlSession.close();              System.out.println(user);          }                    @Test          public void testGetAll(){              SqlSession sqlSession = MyBatisUtil.getSqlSession();              //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来              UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);              //执行查询操作，将查询结果自动封装成List<User>返回              List<User> lstUsers = mapper.getAll();              //使用SqlSession执行完SQL之后需要关闭SqlSession              sqlSession.close();              System.out.println(lstUsers);          }      }  

4.一个原作者封装的MyBatisUtil工具类：

    package me.gacl.util;            import java.io.InputStream;            import org.apache.ibatis.session.SqlSession;      import org.apache.ibatis.session.SqlSessionFactory;      import org.apache.ibatis.session.SqlSessionFactoryBuilder;            public class MyBatisUtil {                /**          * 获取SqlSessionFactory          * @return SqlSessionFactory          */          public static SqlSessionFactory getSqlSessionFactory() {              String resource = "conf.xml";              InputStream is = MyBatisUtil.class.getClassLoader().getResourceAsStream(resource);              SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);              return factory;          }                    /**          * 获取SqlSession          * @return SqlSession          */          public static SqlSession getSqlSession() {              return getSqlSessionFactory().openSession();          }                    /**          * 获取SqlSession          * @param isAutoCommit           *         true 表示创建的SqlSession对象在执行完SQL之后会自动提交事务          *         false 表示创建的SqlSession对象在执行完SQL之后不会自动提交事务，这时就需要我们手动调用sqlSession.commit()提交事务          * @return SqlSession          */          public static SqlSession getSqlSession(boolean isAutoCommit) {              return getSqlSessionFactory().openSession(isAutoCommit);          }      }