Mybatis概要

使用Mybatis把握四个要点：

1.Mybatis配置文件mybatis-config.xml

2.Mybatis映射文件MyMapper.xml

3.对应映射文件的接口MyMapper.java

4.实体类My.java

1.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>    <properties resource="properties/mybatis-config.properties">        <property name="username" value="test"/>        <property name="password" value="test123"/>    </properties>    <settings>        <!--配置默认的执行器:重用预处理语句-->        <setting name="defaultExecutorType" value="REUSE"/>    </settings>    <typeAliases>        <typeAlias alias="Student" type="com.agcro.myapp.model.Student"/>    </typeAliases>    <environments default="development">        <environment id="development">            <transactionManager type="JDBC"/>            <dataSource type="POOLED">                <property name="driver" value="${driver}"/>                <property name="url" value="${url}"/>                <property name="username" value="${username}"/>                <property name="password" value="${password}"/>            </dataSource>        </environment>    </environments>    <mappers>        <mapper resource="com/agcro/myapp/data/StudentMapper.xml"/>    </mappers></configuration>

2.MyMapper.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="com.agcro.myapp.data.StudentMapper">    <resultMap id="studentResultMap" type="Student">        <id property="id" column="id"/>        <result property="name" column="name"/>        <result property="gender" column="gender"/>        <result property="major" column="major"/>        <result property="grade" column="grade"/>    </resultMap>    <select id="getById" parameterType="int" resultMap="studentResultMap">        select * from student where id=#{id}    </select></mapper>

3.映射接口文件MyMapper.java

package com.agcro.myapp.data;import com.agcro.myapp.model.Student;/** * Created by x on 13-6-23. */public interface StudentMapper {    public Student getById(int id);}

4.实体类My.java

public class Student {    private int id;    private String name;    private String gender;    private String major;    private String grade;    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 String getGender() {        return gender;    }    public void setGender(String gender) {        this.gender = gender;    }    public String getMajor() {        return major;    }    public void setMajor(String major) {        this.major = major;    }    public String getGrade() {        return grade;    }    public void setGrade(String grade) {        this.grade = grade;    }}

最后是业务测试

import com.agcro.myapp.data.StudentMapper;import com.agcro.myapp.model.Student;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 java.io.IOException;import java.io.Reader;/** * Created by x on 13-6-23. */public class test {    public static void main(String[] args)    {        //mybatis-config.xml中的mapper配置类似，告诉MyBatis        //应读取的核心配置文件        String resource = "com/agcro/myapp/data/mybatis-config.xml";        Reader reader = null;        try{            reader = Resources.getResourceAsReader(resource);        }catch(IOException e)        {            e.printStackTrace();        }        //创建SqlSessionFactory实例。没有指定要用到的        //environment，则使用默认的environment        SqlSessionFactory sqlSessionFactory                = new SqlSessionFactoryBuilder().build(reader);        SqlSession sqlSession = sqlSessionFactory.openSession();        try{            StudentMapper mapper =                    sqlSession.getMapper(StudentMapper.class);            Student student = mapper.getById(1);            if(student != null)            {                System.out.println("姓名： "+student.getName()                        +"\n专业： "+student.getMajor());            }            else            {                System.out.println("没有找到。");            }        }        finally        {            sqlSession.close();        }    }}

最后补充上面.properties配置文件mybatis-config.properfies

#数据库driver=com.mysql.jdbc.Driverurl=jdbc:mysql://127.0.0.1:3306/testusername=testpassword=test123