一、使用MyBatis对表执行CRUD操作-基于XML的实现
1、定义sql映射xml文件:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- 为这个mapper指定一个唯一的namespace,namespace的值习惯上设置成包名+sql映射文件名,这样就能够保证namespace的值是唯一的
例如namespace="me.gacl.mapping.userMapper"就是me.gacl.mapping(包名)+userMapper(userMapper.xml文件去除后缀)
-->
<mapper namespace="me.gacl.mapping.userMapper">
<!-- 在select标签中编写查询的SQL语句, 设置select标签的id属性为getUser,id属性值必须是唯一的,不能够重复
使用parameterType属性指明查询时使用的参数类型,resultType属性指明查询返回的结果集类型
resultType="me.gacl.domain.User"就表示将查询结果封装成一个User类的对象返回
2.
创建用户(Create):
<insert id="addUser" parameterType="me.gacl.domain.User">
insert into users(name,age) values(#{name},#{age})
</insert>
删除用户(Remove):
“`
delete from users where id=#{id}
修改用户(Update):
update users set name=#{name},age=#{age} where id=#{id}
s
查询全部用户:
elect id=”getAllUsers” resultType=”me.gacl.domain.User” select * from users
select
二、使用MyBatis对表执行CRUD操作-基于注解的实现
1、定义sql映射的接口
UserMapperI接口的代码如下:
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}”)
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 getAll();
}
2、在conf.xml文件中注册这个映射接口:
单元测试类:
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返回
List lstUsers = mapper.getAll();
//使用SqlSession执行完SQL之后需要关闭SqlSession
sqlSession.close();
System.out.println(lstUsers);
}
}
MyBatisUtil工具类:
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;
}
public static SqlSession getSqlSession() {
return getSqlSessionFactory().openSession();
}
public static SqlSession getSqlSession(boolean isAutoCommit) {
return getSqlSessionFactory().openSession(isAutoCommit);
}}
“`