mybatis基础教程之二：接口的方式编程



                        前面一节，已经搭建好了myeclipse,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：
session.selectOne("com.yihaomen.mybatis.models.UserMapper.selectUserByID", 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UserInterface.class），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:
1、在源码目录下建立com.mybaties.entry这个包，并建立接口类 UserInterface和实体类User , 内容如下：
实体类：User.class

package com.mybaties.entry;import java.io.Serializable;public class User implements Serializable {/** *  */private static final long serialVersionUID = 1L;private String id;private String username;private String password;private String name;private String sex;private String email;private String company_name;private String phone;private String post_city;private String post_area;private String post_add;private String relation_person;private String relation_phone;public String getId() {return id;}public void setId(String id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public String getCompany_name() {return company_name;}public void setCompany_name(String company_name) {this.company_name = company_name;}public String getPhone() {return phone;}public void setPhone(String phone) {this.phone = phone;}public String getPost_city() {return post_city;}public void setPost_city(String post_city) {this.post_city = post_city;}public String getPost_area() {return post_area;}public void setPost_area(String post_area) {this.post_area = post_area;}public String getPost_add() {return post_add;}public void setPost_add(String post_add) {this.post_add = post_add;}public String getRelation_person() {return relation_person;}public void setRelation_person(String relation_person) {this.relation_person = relation_person;}public String getRelation_phone() {return relation_phone;}public void setRelation_phone(String relation_phone) {this.relation_phone = relation_phone;}}

接口类：UserInterface.class

package com.mybaties.entry;import java.util.List;//User 接口定义public interface UserInterface {       public int insert(User user);        public int update(User user);        public int delete(String userName);        public List<User> selectAll();        public int countAll();        public User findByUserName(String userName);}

请注意，这里面有一个方法名insert()、update()、deleted（）等方法 必须与 User.xml 里面配置的 select 的id 对应（<select id="insert"）等。

User.xml文件

<?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.mybaties.entry.UserInterface">                <select id="countAll" resultType="int">        select count(*) c from user;    </select>        <select id="selectAll" resultType="com.mybaties.entry.User">        select * from user;    </select>        <insert id="insert" parameterType="com.mybaties.entry.User">        insert into user(id,name,password,sex,email,company_name,phone,post_city,post_area,post_add,relation_person,relation_phone) values(#{id},#{name},#{password},#{sex},#{email},#{company_name},#{phone},#{post_city},#{post_area},#{post_add},#{relation_person},#{relation_phone})    </insert>        <update id="update" parameterType="com.mybaties.entry.User">        update user set password=#{password},name=#{name} where id=#{id};    </update>        <delete id="delete" parameterType="String">        delete from user where id=#{id};    </delete>        <select id="findByUserName" parameterType="String" resultType="com.mybaties.entry.User">        select * from user where id=#{id};    </select>                </mapper>

请朋友千万注意：User.xml 中<mapper>工作空间的配置：com.mybaties.entry.UserInterface---指向UserInterface接口，如果工作空间配置的不是这个路径的话，在运行代码时：提示UserInterface接口没有在Configuration.xml 文件中配置。

测试代码：

package com.mybaties.test;import java.io.IOException;import java.io.Reader;import java.util.Iterator;import java.util.List;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.mybaties.entry.User;import com.mybaties.entry.UserInterface;public class Test {/** * @param 测试方法 */public static void main(String[] args) {// TODO Auto-generated method stub SqlSession session = null;try {    String resource = "Configuration.xml";        Reader reader= Resources.getResourceAsReader(resource);        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();        SqlSessionFactory factory = builder.build(reader);                session = factory.openSession();                UserInterface user=session.getMapper(UserInterface.class);                      //执行User 插入操作        User u=new User();        u.setCompany_name("4");        u.setEmail("4");        u.setId("4");        u.setPassword("4");        u.setPhone("4");        u.setPost_add("4");        u.setPost_area("4");        u.setPost_city("4");        u.setRelation_person("4");        u.setRelation_phone("4");        u.setSex("4");        u.setName("4");                user.insert(u);        System.out.println("记录条数："+user.countAll());        //执行User 查询操作        List<User> users = user.selectAll();        Iterator<User> iter = users.iterator();        while(iter.hasNext()){            User us = iter.next();            System.out.println("用户名："+us.getUsername()+"密码："+us.getPassword());        }        //执行User 数据更改        u.setName("张三");        u.setPassword("123456789");                user.update(u);              /*  User user = (User) session.selectOne("com.mybaties.entry.UserMapper.selectUserByID",1);        System.out.println(user.getName());        System.out.println(user.getPassword());*/} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();} session.commit(); session.close();}

效果截图：