前面一章Mybatis入门概述及第一个Mybatis实例实现增删改查 ，已经搭建好了eclipse,mybatis,mysql的环境，并且实现了一个简单的查询。请注意，这种方式是用SqlSession实例来直接执行已映射的SQL语句：

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1session.selectOne("com.mucfc.model.EmployeerMapper.findEmployeerByID", 1);其实还有更简单的方法，而且是更好的方法，使用合理描述参数和SQL语句返回值的接口（比如EmployeerMapper.java），这样现在就可以至此那个更简单，更安全的代码，没有容易发生的字符串文字和转换的错误.下面是详细过程:

本文要改成以接口类来实现增删改查

整个工程目录 ：

本文示例工程免费下载

1、首先还是mybatis的配置文件mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>

br>PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">

其中配置文件mysql.propertiesdriver=com.mysql.jdbc.Driverurl=jdbc:mysql://localhost:3306/test?charset=utf8username=rootpassword=christmas258@

2、数据表对应的类Employeer.JAVA

package com.mucfc.model;

import java.io.Serializable;

/**

• 雇员信息类
  *@author linbingwen

*@time 2015.5.11

*/public class Employeer {

private Integer employeer_id;private String employeer_name;private Integer employeer_age ;private String employeer_department;private String employeer_worktype; public Employeer() {    super();}public Integer getEmployeer_id() {    return employeer_id;}public void setEmployeer_id(Integer employeer_id) {    this.employeer_id = employeer_id;}public String getEmployeer_name() {    return employeer_name;}public void setEmployeer_name(String employeer_name) {    this.employeer_name = employeer_name;}public Integer getEmployeer_age() {    return employeer_age;}public void setEmployeer_age(Integer employeer_age) {    this.employeer_age = employeer_age;}public String getEmployeer_department() {    return employeer_department;}public void setEmployeer_department(String employeer_department) {    this.employeer_department = employeer_department;}public String getEmployeer_worktype() {    return employeer_worktype;}public void setEmployeer_worktype(String employeer_worktype) {    this.employeer_worktype = employeer_worktype;}@Overridepublic String toString() {    return "Employeer [employeer_id=" + employeer_id + ", employeer_name="            + employeer_name + ", employeer_age=" + employeer_age            + ", employeer_department=" + employeer_department            + ", employeer_worktype=" + employeer_worktype + "]";}

}

然后是SQL语句的配置Employeer.xml：

<?xml version="1.0" encoding="UTF-8" ?>

br>"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

          select* from `t_employeer` where employeer_id =#{employeer_id}           
          
       
    
             insert into `t_employeer`(employeer_name,employeer_age,employeer_department,employeer_worktype)       values(#{employeer_name},#{employeer_age},#{employeer_department},#{employeer_worktype})    
            
      
    
             delete from `t_employeer` where employeer_id = #{employeer_id}    
           
        
    
             update t_employeer set employeer_name = #{employeer_name},employeer_age= #{employeer_age},employeer_department = #{employeer_department}      ,employeer_worktype=#{employeer_worktype}  where employeer_id = #{employeer_id}    
    

?1

注意com.mucfc.mapper.EmployeerMapper这个类是存在的，它是一个接口类，上一讲我们是使用com.mucfc.model.EmployeerMapper，而上一讲的这个类是不存在的

4、SQL语句映射类EmployeerMapper.java

package com.mucfc.mapper;

import com.mucfc.model.Employeer;

/**

• SQL语句映射类
• @author linbingwen
• @time 2015.5.11
  */

public interface EmployeerMapper {

/** * 注意要和Employeer.xml的方法名对应 */public Employeer findEmployeerByID(int id);/** * 注意要和Employeer.xml的方法名对应 */public void addEmployeer(Employeer employeer);/** * 注意要和Employeer.xml的方法名对应 */public void deleteEmployeer(int id);/** * 注意要和Employeer.xml的方法名对应 */public void updateEmployeer(Employeer employeer);

}

5、测试：

（1）增加命令

上一讲Mybatis入门概述及第一个Mybatis实例实现增删改查 中的方式：

/**

• 增加
  */

public static void addEmployeer(Employeer employeer){

SqlSession session = null;try {    session = sqlSessionFactory.openSession();     //返回值是记录条数      int resultCount = session.insert("com.mucfc.model.EmployeerMapper.addEmployeer", employeer );      System.out.printf("当前插入的employeer_id :%d    当前插入数据库中条数:%d " , employeer.getEmployeer_id() ,resultCount);  //获取插入对象的id      System.out.println("");    session.commit() ;          } finally {    session.close();}

}

改成以接口编程的方式：

/**

• 增加
  */

public static void addEmployeer(Employeer employeer){

SqlSession session = null;try {    session = sqlSessionFactory.openSession();    EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);    employeerMapper.addEmployeer(employeer);    session.commit() ;          } finally {    session.close();}

}

（2）删除命令

上一讲【Mybatis】Mybatis入门概述及第一个Mybatis实例实现增删改查 中的方式：

/**

• 删除
• */

public static void deleteEmployeer(int id){

SqlSession session = null;try {    session = sqlSessionFactory.openSession();     //返回值是记录条数       int resultCount=session.delete("com.mucfc.model.EmployeerMapper.deleteEmployeer",id);       System.out.println("当前删除数据库中条数: "+resultCount);  //获取插入对象的id      session.commit() ;          } finally {    session.close();}

}

改成以接口编程的方式：

/**

• 删除
• */

public static void deleteEmployeer(int id){

SqlSession session = null;try {    session = sqlSessionFactory.openSession();    EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);    employeerMapper.deleteEmployeer(id);    session.commit() ;          } finally {    session.close();}

}

（3）查找命令

上一讲【Mybatis】Mybatis入门概述及第一个Mybatis实例实现增删改查 中的方式：

/**

• 查找
  */

public static void findEmployeerById(int id) {

SqlSession session = null;try {    session = sqlSessionFactory.openSession();    Employeer employeer = (Employeer) session.selectOne(            "com.mucfc.model.EmployeerMapper.findEmployeerByID", 1);    if (employeer == null)        System.out.println("null");    else        System.out.println(employeer);} finally {    session.close();}

}

改成以接口编程的方式：

/**

* 查找 */public static void findEmployeerById(int id) {    SqlSession session = null;    try {        session = sqlSessionFactory.openSession();        EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);        Employeer employeer=employeerMapper.findEmployeerByID(id);        if (employeer == null)            System.out.println("null");        else            System.out.println(employeer);    } finally {        session.close();    }}

（4）修改命令

上一讲【Mybatis】Mybatis入门概述及第一个Mybatis实例实现增删改查 中的

/**

• 更改
  */

public static void updateEmployeer(Employeer employeer){

SqlSession session = null;try {    session = sqlSessionFactory.openSession();     session.update("com.mucfc.model.EmployeerMapper.updateEmployeer",employeer);        session.commit() ;          } finally {    session.close();}

}

改成以接口编程的方式：

/**

• 更改
  */

public static void updateEmployeer(Employeer employeer){

SqlSession session = null;try {    session = sqlSessionFactory.openSession();     EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);    employeerMapper.updateEmployeer(employeer);    session.commit() ;          } finally {    session.close();}

}

这是一个完整的测试：

package com.mucfc.test;

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.mucfc.mapper.EmployeerMapper;

import com.mucfc.model.Employeer;

public class MybatisTest {

private static SqlSessionFactory sqlSessionFactory;private static Reader reader;static {    try {        reader = Resources.getResourceAsReader("mybatis-config.xml");        sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);    } catch (Exception e) {        e.printStackTrace();    }}/** * 查找 */public static void findEmployeerById(int id) {    SqlSession session = null;    try {        session = sqlSessionFactory.openSession();        EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);        Employeer employeer=employeerMapper.findEmployeerByID(id);        if (employeer == null)            System.out.println("null");        else            System.out.println(employeer);    } finally {        session.close();    }}/** * 增加 */public static void addEmployeer(Employeer employeer){    SqlSession session = null;    try {        session = sqlSessionFactory.openSession();        EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);        employeerMapper.addEmployeer(employeer);        session.commit() ;              } finally {        session.close();    }     }/** * 删除 *  */public static void deleteEmployeer(int id){    SqlSession session = null;    try {        session = sqlSessionFactory.openSession();        EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);        employeerMapper.deleteEmployeer(id);        session.commit() ;              } finally {        session.close();    }}/** * 更改 */public static void updateEmployeer(Employeer employeer){    SqlSession session = null;    try {        session = sqlSessionFactory.openSession();         EmployeerMapper employeerMapper=session.getMapper(EmployeerMapper.class);        employeerMapper.updateEmployeer(employeer);        session.commit() ;              } finally {        session.close();    }     }public static void main(String[] args) {                                Employeer employeer1=new Employeer();    employeer1.setEmployeer_name("李四");    employeer1.setEmployeer_age(23);    employeer1.setEmployeer_department("产品一部");    employeer1.setEmployeer_worktype("开发工程师");         Employeer employeer2=new Employeer();    employeer2.setEmployeer_name("张三");    employeer2.setEmployeer_age(30);    employeer2.setEmployeer_department("产品二部");    employeer2.setEmployeer_worktype("测试工程师");         Employeer employeer3=new Employeer();    employeer3.setEmployeer_name("小王");    employeer3.setEmployeer_age(22);    employeer3.setEmployeer_department("产品三部");    employeer3.setEmployeer_worktype("数据分析师");              Employeer employeer4=new Employeer();    employeer4.setEmployeer_name("明明");    employeer4.setEmployeer_age(22);    employeer4.setEmployeer_department("财会部");    employeer4.setEmployeer_worktype("财务人员");     //插入    addEmployeer(employeer1);    addEmployeer(employeer2);    addEmployeer(employeer3);    addEmployeer(employeer4);    findEmployeerById(26);    deleteEmployeer(27);         //更改    employeer2.setEmployeer_id(28);    employeer2.setEmployeer_age(21);    employeer2.setEmployeer_department("产品四部");    updateEmployeer(employeer2);}

}

测试结果：

插入了4条数据，ID为25~28

然后27号被删除

29号被修改