Mybatis简单的入门之增删改查

一般的过程例如以下
1、加入Mybatis所须要的包，和连接数据库所需的包
2、配置mybatis-config.xml文件

3、配置与pojo相应的映射文件

mybatis-config,xml

<?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>
<typeAliases>
<typeAlias alias="User" type="com.iss.pojo.User" />
</typeAliases>

<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver" />
<property name="url"
value="jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=UTF-8" />
<property name="username" value="root" />
<property name="password" value="root" />
</dataSource>
</environment>
</environments>

<mappers>
<mapper resource="com/iss/pojo/User.xml" />
</mappers>
</configuration>

pojo实体类

package com.iss.pojo;

public class User {
private int id;

private String name;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public User(int id, String name) {
super();
this.id = id;
this.name = name;
}

public User() {
super();
}

}

User.xml

<?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">

<mapper namespace="User">
<select id="selectUser" parameterType="int" resultType="User">
<![CDATA[
select * from user where id = #{id}]]>
</select>
<insert id="insertUser" parameterType="User">

<![CDATA[insert into user
value(#{id},#{name})]]>

</insert>
<delete id="deleteUser" parameterType="int">
delete from user where
id=#{id}

</delete>
<update id="updateUser" parameterType="User">
update user set
name=#{name} where id=#{id}
</update>
</mapper>

Mybatis工具类

package com.iss.util;

import java.io.IOException;
import java.io.Reader;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import com.sun.org.apache.xpath.internal.operations.Gte;

public class MybatisUtil {

private static SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();//类似于Hibernate中Configration

private static SqlSessionFactory sqlSessionFactory;//类似于Hibernate中SessionFactory

// 静态初始化块配置文件在类执行时仅仅载入一次
static {

String resource = "mybatis-config.xml";
Reader reader = null;
try {
reader = Resources.getResourceAsReader(resource);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

sqlSessionFactory = builder.build(reader);
}

private MybatisUtil() {
// TODO Auto-generated constructor stub
}

public static SqlSessionFactoryBuilder getBuilder() {
return builder;
}

public static void setBuilder(SqlSessionFactoryBuilder builder) {
MybatisUtil.builder = builder;
}

public static SqlSessionFactory getSqlSessionFactory() {
return sqlSessionFactory;
}

public static void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
MybatisUtil.sqlSessionFactory = sqlSessionFactory;
}

// 获得sqlSession对象类似于Hibernate中的session
public static SqlSession getSqlSession() {
SqlSession sqlSession = sqlSessionFactory != null ? sqlSessionFactory
.openSession() : null;
return sqlSession;
}

public static void closeSession() {
SqlSession sqlSession = getSqlSession();
if (sqlSession != null) {
sqlSession.close();
}
}

}

UserService

package com.iss.service;

import org.apache.ibatis.session.SqlSession;

import com.iss.pojo.User;
import com.iss.util.MybatisUtil;

public class UserService {

public static User selectUser(int id) {
SqlSession sqlSession = MybatisUtil.getSqlSession();
User user = sqlSession.selectOne("selectUser", 1);
MybatisUtil.closeSession();
return user;
}

public static void insertUser(int id, String name) {

User user = new User();
user.setId(id);
user.setName(name);

SqlSession sqlSession = MybatisUtil.getSqlSession();
sqlSession.insert("insertUser", user);
sqlSession.commit();
MybatisUtil.closeSession();
}

public static void updateUser(int id, String name) {
User user = new User();
user.setId(id);
user.setName(name);

SqlSession sqlSession = MybatisUtil.getSqlSession();
sqlSession.update("updateUser", user);
sqlSession.commit();
MybatisUtil.closeSession();

}

public static void deleteUser(int id) {
SqlSession sqlSession = MybatisUtil.getSqlSession();
sqlSession.delete("deleteUser", id);
sqlSession.commit();
MybatisUtil.closeSession();
}

}

TestUser

package com.iss.test;

import com.iss.pojo.User;
import com.iss.service.UserService;

public class TestUser {

public static void main(String[] args) {

UserService.insertUser(3, "world");
User user = UserService.selectUser(2);
System.out.println(user.getName());
UserService.updateUser(1, "wdy");
System.out.println(UserService.selectUser(2).getName());

UserService.deleteUser(2);
}
}

总结Hibernate 和Mybatis非常相似

基本的差别

Hibernate的映射文件是对表的映射

Mybatis的映射文件是对表操作的一种映射