4.使用接口+xml文件方式编写dao层

<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>

<?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>

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;

}

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>

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();
}

}

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();

}
}