mybatis基础教程之二：接口的方式编程
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2021-03-31 23:21:27
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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 block
e.printStackTrace();
}
session.commit();
session.close();
}效果截图：
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