1 MyBatis入门

源码下载地址：http://download.csdn.net/download/u010349169/7555959

持久化层的工作是什么？
将从数据库中查询得到的数据生成所需要的java对象；将java对象中的数据通过SQL持久化到数据库中

简单的MyBatis实例

1、在pom.xml中添加依赖

例：<url>http://www.mybatis.org</url>  <properties>        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>        <java.version>1.8</java.version>        <junit.version>4.11</junit.version>        <slf4j.version>1.7.5</slf4j.version>        <log4j.version>1.2.17</log4j.version>        <mybatis.version>3.2.2</mybatis.version>        <mysql.version>5.1.21</mysql.version>        <maven.compiler.plugin>2.3.2</maven.compiler.plugin>    </properties>   <dependencies>        <dependency>            <groupId>org.mybatis</groupId>            <artifactId>mybatis</artifactId>            <version>${mybatis.version}</version>        </dependency>               <dependency>            <groupId>mysql</groupId>            <artifactId>mysql-connector-java</artifactId>            <version>${mysql.version}</version>            <scope>runtime</scope>        </dependency>        <dependency>            <groupId>org.slf4j</groupId>            <artifactId>slf4j-log4j12</artifactId>            <version>${slf4j.version}</version>            <scope>runtime</scope>        </dependency>        <dependency>            <groupId>log4j</groupId>            <artifactId>log4j</artifactId>            <version>${log4j.version}</version>            <scope>runtime</scope>        </dependency>        <dependency>            <groupId>junit</groupId>            <artifactId>junit</artifactId>            <version>${junit.version}</version>            <scope>test</scope>        </dependency>  </dependencies>另外要在src/main/resources下加个 log4j.properties

2、在src/main/resources下创建mybatis-config.xml

首先在src/main/resources下创建数据库连接文件application.properties，内容为：jdbc.driverClassName=com.mysql.jdbc.Driverjdbc.url=jdbc:mysql://localhost:3306/mybatisjdbc.username=rootjdbc.password=hehe下面是mybatis-config.xml的内容：<?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>      <!--  数据库连接属性文件     -->      <properties resource="application.properties"/>      <typeAliases>        <package name="com.mybatis3.domain"/>      </typeAliases>      <environments default="development">        <environment id="development">          <transactionManager type="JDBC"/>          <dataSource type="POOLED">            <property name="driver" value="${jdbc.driverClassName}"/>            <property name="url" value="${jdbc.url}"/>            <property name="username" value="${jdbc.username}"/>            <property name="password" value="${jdbc.password}"/>          </dataSource>        </environment>      </environments>      <!-- 映射器   -->      <mappers>        <mapper resource="com/mybatis3/mappers/StudentMapper.xml"/>      </mappers></configuration>

3、创建SQL映射器配置文件 StudentMapper.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.mybatis3.mappers.StudentMapper">    <resultMap type="Student" id="StudentResult">        <id     property="studId" column="stud_id"/>        <result property="name" column="name"/>        <result property="email" column="email"/>        <result property="dob" column="dob"/>    </resultMap>    <select id="findAllStudents" resultMap="StudentResult">        select * from Students    </select>    <select id="findStudentById" parameterType="int" resultType="Student">        select stud_id as studId, name, email, dob from Students where stud_id=#{studId}    </select>    <insert id="insertStudent" parameterType="Student">        INSERT INTO STUDENTS(STUD_ID,NAME,EMAIL,DOB) VALUES(#{studId},#{name},#{email},#{dob})    </insert>    <update id="updateStudent" parameterType="Student">        UPDATE STUDENTS SET NAME=#{name}, EMAIL=#{email}, DOB=#{dob} WHERE STUD_ID=#{studId}    </update></mapper>

4、创建自己的MyBatisSqlSessionFactory.java，里面会用到mybatis-config.xml
5、实体类 Student.java
6、接口 StudentMapper.java ，与上面的StudentMapper.xml对应。

public interface StudentMapper{    List<Student> findAllStudents();    Student findStudentById(Integer id);    void insertStudent(Student student);    void updateStudent(Student student);}

7、StudentService.java
需要用到自己写的MyBatisSqlSessionFactory和StudentMapper，里面方法有：

public List<Student> findAllStudents()public Student findStudentById(Integer studId)public void createStudent(Student student)public void updateStudent(Student student)