4.使用接口+xml文件方式编写dao层

创建maven工程

引入maven依赖

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">  <modelVersion>4.0.0</modelVersion>  <groupId>com.cjq</groupId>  <artifactId>cjq-mybatis1</artifactId>  <version>1.0-SNAPSHOT</version>  <packaging>jar</packaging>  <name>cjq-mybatis1</name>  <url>http://maven.apache.org</url>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  </properties>  <dependencies>    <dependency>      <groupId>junit</groupId>      <artifactId>junit</artifactId>      <version>4.12</version>      <scope>test</scope>    </dependency>    <!--MyBatis相关-->    <dependency>      <groupId>org.mybatis</groupId>      <artifactId>mybatis</artifactId>      <version>3.2.8</version>    </dependency>    <!--数据库相关-->    <dependency>      <groupId>mysql</groupId>      <artifactId>mysql-connector-java</artifactId>      <version>5.1.35</version>    </dependency>  </dependencies></project>

创建主配置文件configuration.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 type="com.cjq.vo.Emp" alias="emp" />    </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://localhost:3306/test"/>                <property name="username" value="root"/>                <property name="password" value="admin"/>            </dataSource>        </environment>    </environments>    <mappers>        <!--加入映射文件-->        <mapper resource="mapper/EmpMapper.xml"/>    </mappers></configuration>

emp表

emp类

package com.cjq.vo;/** * Created by cjq on 2017/9/16. */public class Emp {    public Emp() {    }    public Integer getEno() {        return eno;    }    public Emp(Integer eno, String ename, String job, Double sal) {        this.eno = eno;        this.ename = ename;        this.job = job;        this.sal = sal;    }    @Override    public String toString() {        return "Emp{" +                "eno=" + eno +                ", ename='" + ename + '\'' +                ", job='" + job + '\'' +                ", sal=" + sal +                '}';    }    public void setEno(Integer eno) {        this.eno = eno;    }    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 Double getSal() {        return sal;    }    public void setSal(Double sal) {        this.sal = sal;    }    Integer eno;    String ename;    String job;    Double sal;}

创建接口

package com.cjq.dao;import com.cjq.vo.Emp;/** * Created by cjq on 2017/9/16. */public interface EmpDao {    public void insert(Emp emp);    public void delete(int eno);    public Emp getEmpById(int eno);}

<?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.cjq.dao.EmpDao">     <!-- namespace的值对应接口-->     <!--id对应接口的方法，resultType是返回值类型，parameterType方法传入的参数类型 -->    <!--根据id删除-->      <delete id="delete" parameterType="int">        delete from emp where eno=#{eno}      </delete>    <!--新增-->      <insert id="insert" parameterType="com.cjq.vo.Emp">        insert into emp(eno,ename,job,sal) values(#{eno},#{ename},#{job},#{sal})      </insert>    <!--根据id查询-->      <select id="getEmpById"  parameterType="int" resultType="com.cjq.vo.Emp">           select * from emp where eno=#{value}      </select></mapper>

获取SqlSession的工具类

package com.cjq.dao;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.InputStream;/** * Created by cjq on 2017/9/16. */public class SessionFactory {    static SqlSessionFactory factory=null;    static{        //测试查询        String resource="configuration.xml";        //获取资源的流        InputStream r= null;        try {            r = Resources.getResourceAsStream(resource);        } catch (IOException e) {            e.printStackTrace();        }        //获得session工厂         factory=new SqlSessionFactoryBuilder().build(r);    }    public static SqlSession getSession(){        //openSession默认事物是手动提交的         return factory.openSession();    }}

测试

package com.cjq.vo;import com.cjq.dao.EmpDao;import com.cjq.dao.SessionFactory;import org.apache.ibatis.session.SqlSession;import java.io.IOException;/** * Created by cjq on 2017/9/16. */public class DeptTest {    public static void main(String[] args) throws IOException {        //获取session        SqlSession session= SessionFactory.getSession();        //获得Dao        EmpDao dao=session.getMapper(EmpDao.class);       // dao.insert(new Emp(4,"zhangsan","job1",4000.0));       // Emp emp=dao.getEmpById(4);       // System.out.println(emp);         dao.delete(4);        session.commit();        session.close();    }}