MyBatis 快速入门

MyBatis介绍

MyBatis的前身就是iBatis,iBatis本是apache的一个开源项目，2010年这个项目由apahce sofeware foundation 迁移到了google code，并且改名为MyBatis。

MyBatis优缺点

优点：简单、灵活、高效

缺点：移植性差

开发环境搭建

1、下载需要的MyBatis jar包

2、部署MyBatis jar包

3、编写MyBatis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>
        <typeAliases>
        <typeAlias alias="Emp" type="com.accp.entity.Emp"/>
        </typeAliases>
    <environments default="development">
        <environment id="development">
        <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
            <property name="driver" value="oracle.jdbc.driver.OracleDriver"/>
            <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl"/>
            <property name="username" value="scott"/>
            <property name="password" value="tiger"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com/accp/uitl/EmpDaoMapper.xml"/>
    </mappers>
</configuration>

 4、创建持久化类和数据库接口 

package com.accp.entity;

import java.util.Date;


public class Emp implements java.io.Serializable {

    // Fields
    
    private int empno;
    private String ename;
    private String job;
    private int mgr;
    private Date hiredate;
    private Double sal;
    private Double comm;
    private int deptno;
    // Constructors
    /** default constructor */
    public Emp() {
    }
    
    public Emp(int empno, String ename, String job, int mgr, Date hiredate,
            Double sal, Double comm, int deptno) {
        super();
        this.empno = empno;
        this.ename = ename;
        this.job = job;
        this.mgr = mgr;
        this.hiredate = hiredate;
        this.sal = sal;
        this.comm = comm;
        this.deptno = deptno;
    }

    public int getEmpno() {
        return empno;
    }
    public void setEmpno(int empno) {
        this.empno = empno;
    }
    public String getEname() {
        return ename;
    }
    public void setEname(String ename) {
        this.ename = ename;
    }
    public String getJob() {
        return job;
    }
    public void setJob(String job) {
        this.job = job;
    }
    public int getMgr() {
        return mgr;
    }
    public void setMgr(int mgr) {
        this.mgr = mgr;
    }
    public Date getHiredate() {
        return hiredate;
    }
    public void setHiredate(Date hiredate) {
        this.hiredate = hiredate;
    }
    public Double getSal() {
        return sal;
    }
    public void setSal(Double sal) {
        this.sal = sal;
    }
    public Double getComm() {
        return comm;
    }
    public void setComm(Double comm) {
        this.comm = comm;
    }
    public int getDeptno() {
        return deptno;
    }
    public void setDeptno(int deptno) {
        this.deptno = deptno;
    }




}

package com.accp.dao;

import com.accp.entity.Emp;

public interface IEmpDao {
    public void insertEmp(Emp emp);
    public void updateEmp(Emp emp);
}

5、创建SQL映射文件

<?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.accp.dao.IEmpDao">
    <insert id="insertEmp" parameterType="Emp" >
        INSERT INTO emp(empno,ename,job,mgr,hiredate,sal,comm,deptno)VALUES(#{empno},#{ename},#{job},#{mgr},#{hiredate},#{sal},#{comm},#{deptno})
    </insert>
    <update id="updateEmp" parameterType="Emp">
        UPDATE emp SET ename=#{ename},job=#{job},mgr=#{mgr},sal=#{sal} WHERE empno=#{empno}
    </update>
</mapper>

6、创建书库接口和实现类

package com.accp.daoImpl;

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.accp.dao.IEmpDao;
import com.accp.entity.Emp;
/**
 * @author 孙洪雨
 */
public class IEmpDaoImpl implements IEmpDao {
    SqlSession session=null;
    SqlSessionFactory sf=null;
    Reader reader=null;
    @Override
    public void insertEmp(Emp emp) {
            try {
                String resource="mybatis-config.xml";
                reader=Resources.getResourceAsReader(resource);
                SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder();
                sf=builder.build(reader);
                session=sf.openSession();
                IEmpDao dao=session.getMapper(IEmpDao.class);
                dao.insertEmp(emp);
                session.commit();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally{
                if(session!=null){
                    session.close();
                }
            }
        
    }
    @Override
    public void updateEmp(Emp emp) {
        try {
            String resource="mybatis-config.xml";
            reader=Resources.getResourceAsReader(resource);
            SqlSessionFactoryBuilder bulder=new SqlSessionFactoryBuilder();
            sf=bulder.build(reader);
            session=sf.openSession();
            IEmpDao dao=session.getMapper(IEmpDao.class);
            dao.updateEmp(emp);
            session.commit();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            if(session!=null){
                session.close();
            }
        }
    }

}

7、编写测试类进行测试

使用MyBatis实现数据表的查询

<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.accp.dao.IEmpDao">

<select id="findEmpByEmpNo" parameterType="int" resultType="com.accp.entity.Emp" >
    SELECT empno,ename,job,mgr,hiredate,sal,comm from Emp where  empno= #{empno}
</select>
</mapper>

select元素有如下设置：

1.使用selectOne方法

package com.accp.daoImpl;

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.accp.dao.IEmpDao;
import com.accp.entity.Emp;

public class IEmpDaoImpl implements IEmpDao {
    SqlSessionFactory sf=null;
    SqlSession session=null;
    Reader reader=null;
    @Override
    public Emp findEmpByEmpNo(int empno) {
        String resource="mybatis-config.xml";
        Emp emp=null;
        try {
            reader=Resources.getResourceAsReader(resource);
            SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder();
            sf=builder.build(reader);
            session=sf.openSession();
            emp=session.selectOne("com.accp.dao.IEmpDao.findEmpByEmpNo", empno);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return emp;
    }

}

2.session.getMapper()方法实现

package com.accp.daoImpl;

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.accp.dao.IEmpDao;
import com.accp.entity.Emp;

public class IEmpDaoImpl implements IEmpDao {
    SqlSessionFactory sf=null;
    SqlSession session=null;
    Reader reader=null;
    @Override
    public Emp findEmpByEmpNo(int empno) {
        String resource="mybatis-config.xml";
        Emp emp=null;
        try {
            reader=Resources.getResourceAsReader(resource);
            SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder();
            sf=builder.build(reader);
            session=sf.openSession();
            IEmpDao dao=session.getMapper(IEmpDao.class);
            emp=dao.findEmpByEmpNo(empno);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return emp;
    }

}

 使用MyBatis实现结果映射

<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.accp.dao.IEmpDao">

<resultMap type="com.accp.entity.Emp" id="ResultMap">
    <id property="empno" column="empno"/>
    <result property="ename" column="ename"/>
    <result property="job" column="job"/>
    <result property="mgr" column="mgr"/>
    <result property="hiredate" column="hiredate"/>
    <result property="sal" column="sal"/>
    <result property="comm" column="comm"/>
</resultMap>
<select id="empResultMap" resultMap="ResultMap">
    select * from EMP 
</select>
</mapper>

  使用MyBatis实现数据表增删改操作

MyBatis的官方网站是https://code.google.com/p/mybatis/