一、MyBatis简介

</br>

1、MyBatis的优点

</br>

消除了大量的JDBC冗余代码
低学习曲线
友好的Spring集成支持
除本身的缓存外，能友好的第三方缓存类库集成支持
良好的性能

</br>

2、MyBatis简单实例

</br>

创建表

create table t_person
(
    id int auto_increment not null primary key,
    name varchar(20) not null,
    age int,
    address varchar(50)
);

sql配置文件

<?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>
    <!-- 数据库连接的环境，可以配置多个环境 -->
    <environments default="hello_mysql">
        <!-- 环境 -->
        <environment id="hello_mysql">
            <!-- 事务管理的策略  type = "jdbc" or "managed" -->
            <transactionManager type="jdbc"/>
            <!-- 数据源 type = "pooled"连接池   or "unpooled"不用连接池 or "jndi"跟Spring用 -->
            <dataSource type="pooled">
                <property name="driver" value="org.gjt.mm.mysql.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/test"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
    
    <!-- 加载配置文件PersonMapper.xml -->
    <mappers>
        <mapper resource="com/xiao/mybatis/pojo/PersonMapper.xml"/>
    </mappers>
    
</configuration>

pojo类

package com.xiao.mybatis.pojo;

public class Person {

    private int pid;
    private String pname;
    private int age;
    private String address;
    
    public Person() {
        
    }
    
    public Person(String pname,int age,String address){
        this.pname = pname;
        this.age = age;
        this.address = address;
    }

    public int getPid() {
        return pid;
    }

    public void setPid(int pid) {
        this.pid = pid;
    }

    public String getPname() {
        return pname;
    }

    public void setPname(String pname) {
        this.pname = pname;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String toString() {
        return "Person [pid=" + pid + ", pname=" + pname + ", age=" + age
                + ", address=" + address + "]";
    }
    
}

pojo配置文件

<?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">

<mapper namespace="com.xiao.mybatis.pojo">
    <!-- 插入 -->
    <insert id="addPerson" parameterType="com.xiao.mybatis.pojo.Person" useGeneratedKeys="true" keyProperty="pid">
        insert into t_person values(null,#{pname},#{age},#{address})
    </insert>
    <!-- 查询 -->
    <select id="getPersonList" resultType="com.xiao.mybatis.pojo.Person">
        select * from t_person
    </select>
    <select id="getPersonByPid" parameterType="int" resultType="com.xiao.mybatis.pojo.Person">
        select * from t_person where pid = #{pid}
    </select>
    <!-- 更新 -->
    <update id="updatePesron" parameterType="com.xiao.mybatis.pojo.Person">
        update t_person set pname = #{pname} , age = #{age} , address = #{address} where pid = #{pid}
    </update>
    <!-- 删除 -->
    <delete id="deletePerson" parameterType="int">
        delete from t_person where pid = #{pid}
    </delete>
</mapper>

测试类

package com.xiao.mybatis.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

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.xiao.mybatis.pojo.Person;

public class PersonDaoTest {

    SqlSession session = null;

    /**
     * 在连接数据库前加载
     */
    public void setUp() {

        try {
            // 1、加载配置文件sqlMapConfig.xml
            InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");

            // 2、解析配置文件sqlMapConfig.xml
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(resourceAsStream);

            // 3、通过factory创建session对象
            session = factory.openSession();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    
    /**
     * 执行完操作后提交事务，以及关闭连接
     */
    public void tearDown() {
        // 5、提交或回滚
        session.commit();// session.rollback();

        // 6、关闭session
        if (null != session) {
            session.close();
        }
    }

    // 一、插入数据
    public void addPersonTest() {

        setUp();

        Person person = new Person("boss", 20, "China");

        // 4、执行插入操作
        int count = session.insert("com.xiao.mybatis.pojo.addPerson", person);
        
        System.out.println(count > 0 ? "插入成功" : "插入失败");
        
        tearDown();
    }

    // 二、查询数据
    public void selectPersonTest() {

        setUp();

        List personList = session.selectList("com.xiao.mybatis.pojo.getPersonList");
        
        System.out.println( null != personList ? "查询成功" : "查询失败");

        if(null != personList){
            System.out.println(personList.toString());
        }
            
        tearDown();
    }
    
    // 二、条件查询数据
    public void selectPersonByIdTest() {

        setUp();

        Person person = (Person) session.selectOne("com.xiao.mybatis.pojo.getPersonByPid",new Integer(7));
        
        System.out.println( null != person ? "查询数据成功" : "查询失败");
        
        if(null != person){
            System.out.println(person.toString());
        }
        
        tearDown();
    }
    
    // 三、修改数据
    public void updatePersonTest(){
        setUp();

        Person person = new Person(5,"boss", 100, "America");
        
        int count = session.update("com.xiao.mybatis.pojo.updatePesron", person);
        
        System.out.println(count > 0 ? "修改成功" : "修改失败");
        
        tearDown();
    }
    
    // 四、删除数据
    
    public void deletePersonTest(){
        setUp();
        
        Person person = new Person(5,"boss", 100, "America");
        
        int count = session.delete("com.xiao.mybatis.pojo.deletePerson", person);
        
        System.out.println(count > 0 ? "删除成功" : "删除失败");
        
        tearDown();
    }

    public static void main(String[] args) {
        PersonDaoTest personDaoTest = new PersonDaoTest();  

        //personDaoTest.addPersonTest();        // 插入
        //personDaoTest.selectPersonTest();     // 查询
        personDaoTest.selectPersonByIdTest();
        //personDaoTest.updatePersonTest();     // 修改
        //personDaoTest.deletePersonTest();     // 删除
        
    }
}