JavaWeb_(Mybatis框架)输入和输出参数_五

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　　　　JavaWeb_(Mybatis框架)主配置文件介绍_四　　　　　　　　　　　　　　　 　　   传送门

　　　　JavaWeb_(Mybatis框架)输入和输出参数_五　　　　　　　　　　　　　　　　　　 传送门

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　　1、输入映射parameterType；
　　　　a)基本类型；
　　　　b)自定义对象； 
　　　　c)自定义包装类；
　　2、输出映射resultType、resultMap；
　　　　a)resultType：
　　　　　　i.基本类型；
　　　　　　ii.自定义对象；
　　　　　　iii.集合； 
　　　　b)resultMap；
　　　　　　i.bean对象字段与数据表字段不匹配；
　　　　　　ii.自定义包装类；
　　　　　　iii.关联查询；

　　

1、输入映射parameterType[废弃的]

　　创建一个自定义对象UserVo

package com.Gary.bean;
 
//包装类
public class UserVo {
 
    //包装类
 
    //需要全部的user对象信息
    private User user;
 
    public User getUser() {
        return user;
    }
 
    public void setUser(User user) {
        this.user = user;
    }
 
    //需要表B的id name 属性
 
}

UserVo.java

　　在UserMapper接口中定义一个selectUserByVoId(UserVo id)方法，通过UserVo id 查询一个用户

package com.Gary.mapper;
 
import java.util.List;
 
import com.Gary.bean.User;
import com.Gary.bean.UserVo;
 
public interface UserMapper {
 
    //通过id查询一个用户
    public User selectUserById(Integer id);
 
    //通过用户名模糊查询 获取用户列表
    public List<User> selectUserByName(String name);
 
    //通过UserVo id 查询一个用户
    public User selectUserByVoId(UserVo id);
 
}

UserMapper.java

　　在UserMapper.xml中实现这个查询方法

     <!-- 根据UserVo中的User对象的u_id去查询查询用户 -->
     <select id="selectUserByVoId" parameterType="UserVo" resultType="user">
         select * from user where u_id = #{user.u_id}
     </select>

<?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.Gary.mapper.UserMapper">
 
     <select id="selectUserById" parameterType="Integer" resultType="user">
         select * from user where u_id = #{id}
     </select>
 
     <!-- #{}占位符 尽量使用#{}来解决问题 -->
     <!-- ${}字符串拼接   容易sql注入 (or 1 = 1) -->
 
     <!-- ${value}中间的字符串一定需要使用value -->
     <select id="selectUserByName" parameterType="String" resultType="com.Gary.bean.User">
         <!-- select * from user where u_username like '%${value}%' -->
              select * from user where u_username like "%"#{name}"%"
     </select>
 
     <!-- 添加用户 参数为全包名 -->
     <insert id="insertUser" parameterType="com.Gary.bean.User">
         insert into user values(null,#{u_username},#{u_password},#{u_sex},#{u_createTime},#{u_cid})
     </insert>
 
    <!-- 根据id修改username字段的语句 -->
     <update id="updateUser" parameterType="com.Gary.bean.User">
         update user set u_username = #{u_username} where u_id = #{u_id}
     </update>
 
     <!-- 根据id删除用户 -->
     <delete id="deleteUserById" parameterType="Integer">
         delete from user where u_id = #{id}
     </delete>
 
     <!-- 根据UserVo中的User对象的u_id去查询查询用户 -->
     <select id="selectUserByVoId" parameterType="UserVo" resultType="user">
         select * from user where u_id = #{user.u_id}
     </select>
 
</mapper>

UserMapper.xml

　　测试

　　

package com.Gary.test;
 
import java.io.IOException;
import java.io.InputStream;
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 org.junit.Test;
 
import com.Gary.bean.User;
import com.Gary.bean.UserVo;
import com.Gary.mapper.UserMapper;
 
public class MapperTest3 {
 
    @Test
    public void Test3() throws IOException {
        //读取配置文件
        String resource = "sqlMapConfig.xml";
 
        InputStream in = Resources.getResourceAsStream(resource);
 
        //创建sqlSessionFactory
        SqlSessionFactory ssf = new SqlSessionFactoryBuilder().build(in);
 
        //生产一个sqlSession
        SqlSession session = ssf.openSession();
 
        UserMapper mapper = session.getMapper(UserMapper.class);
 
        UserVo vo = new UserVo();
        User u= new User();
        u.setU_id(5);
        vo.setUser(u);
 
        User user = mapper.selectUserByVoId(vo);
        System.out.println(user);
 
    }
 
}

MapperTest3.java

2、输出映射resultType

　　实现查询数据库中总条数

　　在CountryMapper.java中编写接口selectAll()，UserMapper.xml中是实现selectUserCount查询用户总条数sql语句

    <!-- 查询用户的总条数 -->
    <select id="selectUserCount" resultType="Integer">
        select count(*) from user
    </select>    

<?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.Gary.mapper.UserMapper">
 
     <select id="selectUserById" parameterType="Integer" resultType="user">
         select * from user where u_id = #{id}
     </select>
 
     <!-- #{}占位符 尽量使用#{}来解决问题 -->
     <!-- ${}字符串拼接   容易sql注入 (or 1 = 1) -->
 
     <!-- ${value}中间的字符串一定需要使用value -->
     <select id="selectUserByName" parameterType="String" resultType="com.Gary.bean.User">
         <!-- select * from user where u_username like '%${value}%' -->
              select * from user where u_username like "%"#{name}"%"
     </select>
 
     <!-- 添加用户 参数为全包名 -->
     <insert id="insertUser" parameterType="com.Gary.bean.User">
         insert into user values(null,#{u_username},#{u_password},#{u_sex},#{u_createTime},#{u_cid})
     </insert>
 
    <!-- 根据id修改username字段的语句 -->
     <update id="updateUser" parameterType="com.Gary.bean.User">
         update user set u_username = #{u_username} where u_id = #{u_id}
     </update>
 
     <!-- 根据id删除用户 -->
     <delete id="deleteUserById" parameterType="Integer">
         delete from user where u_id = #{id}
     </delete>
 
     <!-- 根据UserVo中的User对象的u_id去查询查询用户 -->
     <select id="selectUserByVoId" parameterType="UserVo" resultType="user">
         select * from user where u_id = #{user.u_id}
     </select>
 
     <!-- 查询用户的总条数 -->
     <select id="selectUserCount" resultType="Integer">
         select count(*) from user
     </select>
 
</mapper>

UserMapper.xml

package com.Gary.test;
 
import java.io.IOException;
import java.io.InputStream;
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 org.junit.Test;
 
import com.Gary.bean.User;
import com.Gary.bean.UserVo;
import com.Gary.mapper.UserMapper;
 
public class MapperTest4 {  
 
    @Test
    public void Test4() throws IOException {
        //读取配置文件
        String resource = "sqlMapConfig.xml";
 
        InputStream in = Resources.getResourceAsStream(resource);
 
        //创建sqlSessionFactory
        SqlSessionFactory ssf = new SqlSessionFactoryBuilder().build(in);
 
        //生产一个sqlSession
        SqlSession session = ssf.openSession();
 
        UserMapper mapper = session.getMapper(UserMapper.class);
 
        Integer count = mapper.selectUserCount();
        System.out.println(count);
 
    }
 
}

MapperTest4.java

3、输出映射resultMap

　　创建一个Country.class

package com.Gary.bean;
 
public class Country {
 
    private Integer id;
    private String c_countryname;
    private String c_capital;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getC_countryname() {
        return c_countryname;
    }
    public void setC_countryname(String c_countryname) {
        this.c_countryname = c_countryname;
    }
    public String getC_capital() {
        return c_capital;
    }
    public void setC_capital(String c_capital) {
        this.c_capital = c_capital;
    }
    @Override
    public String toString() {
        return "Country [id=" + id + ", c_countryname=" + c_countryname + ", c_capital=" + c_capital + "]";
    }
 
}

Country.java

　　在CountryMapper.java接口中定义一个查询所有国家的方法selectAll()

package com.Gary.mapper;
 
import java.util.List;
 
import com.Gary.bean.Country;
 
public interface CountryMapper {
 
    //查询所有
    List<Country> selectAll();
 
}

CountryMapper.java

　　在CountryMapper.xml中编写Sql查询语句，因为数据库中没有id这个属性类名，所以需要一个<resultMap>去将id映射成c_id

<mapper namespace="com.Gary.mapper.CountryMapper">
 
    <resultMap type="Country" id="country">
        <result property="id" column="c_id"/>
    </resultMap>
 
    <!-- 查询所有 -->
    <select id="selectAll" resultMap="country">
        select * from country
    </select>
 
</mapper>

<?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.Gary.mapper.CountryMapper">
 
    <resultMap type="Country" id="country">
        <result property="id" column="c_id"/>
    </resultMap>
 
    <!-- 查询所有 -->
    <select id="selectAll" resultMap="country">
        select * from country
    </select>
 
</mapper>

CountryMapper.xml

　　

package com.Gary.test;
 
import java.io.IOException;
import java.io.InputStream;
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 org.junit.Test;
 
import com.Gary.bean.Country;
import com.Gary.bean.User;
import com.Gary.bean.UserVo;
import com.Gary.mapper.CountryMapper;
import com.Gary.mapper.UserMapper;
 
public class MapperTest5 {  
 
    @Test
    public void Test4() throws IOException {
        //读取配置文件
        String resource = "sqlMapConfig.xml";
 
        InputStream in = Resources.getResourceAsStream(resource);
 
        //创建sqlSessionFactory
        SqlSessionFactory ssf = new SqlSessionFactoryBuilder().build(in);
 
        //生产一个sqlSession
        SqlSession session = ssf.openSession();
 
        CountryMapper mapper = session.getMapper(CountryMapper.class);
 
        List<Country> list = mapper.selectAll();
 
        for(Country country:list)
        {
            System.out.println(country);
        }
 
    }
 
}

MapperTest5.java