NIIT实训（春季 git + Maven + Springboot + MyBatis + Vue）第三次
文章目录
-
- DAY7
-
- 使用map传递参数
- $ 和
- 模糊查询：
- DAY8
-
- resultMap
- where的使用
- update
- trim
- 根据数组查询
- 批量插入：
- 代码复用
- DAY10
-
- 缓存
- DAY11
DAY7
使用map传递参数
<select id="selectUserByMap" resultType="User">
select * from tb_user where username=#{username}
and password=#{password}
and phone=#{phone}
and email=#{email}
</select>
mapper文件
User selectUserByMap(Map ma);
@Test
public void testSelectUserByMap(){
Map map = new HashMap<>();
map.put("username", "123");
map.put("password", "123");
map.put("phone", "123");
map.put("email","123");
User user = userMapper.selectUserByMap(map);
System.out.println("多个简单类型，testSelectUserByUsernamePassword = "
+ user);
}
$ 和
<select id="selectByField" resultType="com.example.demomybatis.pojo.User">
select *
from tb_user
where ${colName} = #{colVal}
</select>
User selectByField(String colName, String colVal);
@Test
public void testSelectByField(){
//防止SQL注入
String colName = "1=1 or username";
String colName = "username";
String colVal = "123";
//User user = userMapper.selectByField(colName, colVal);
List<User> users = userMapper.selectByFieldForList(colName, colVal);
}
模糊查询：
where username like concat('%', #{username}, '%')
DAY8
resultMap
<!-- resultMap:开发人员自定义返回列与Java实体对象属性的映射-->
<!-- 1、指定java实体对象类型，通过type属性进行指定;可以类完全限定名称或别名-->
<!-- 2、可以映射数据库表列名与实体类属性名;-->
<!-- 3、-一对一映射、一对多映射-->
<!-- id属性: Mapper 映射文件中的唯一标识，-->
<!-- <id>元素:建立主键的映射关系-->
<!-- <result>元素:非主键的映射-->
<resultMap id="BaseUserResultMap" type="User">
<!-- 列与实体类属性名的映射 -->
<id column="id" property="id"></id>
<result column="username" property="username"></result>
<result column="password" property="password"></result>
<result column="phone" property="phone"></result>
<result column="email" property="email"></result>
<result column="age" property="age"></result>
<result column="gmt_create" property="gmtCreate"></result>
<result column="login_time" property="loginTime"></result>
</resultMap>
<select id="selectByUserForResultMap" resultMap="BaseUserResultMap">
SELECT
`id`,
`username`,
`password`,
`age`,
`phone`,
`email`,
`gmt_create`,
`login_time`
from tb_user
where username=#{username}
</select>
@Test
public void testSelectByUserForResultMap(){
User paramUser = new User( ) ;
paramUser.setUsername( "123");
User user = userMapper.selectByUserForResultMap(paramUser);
System.out.println("练习使用 resultMap, user= " + user);
user = userMapper.selectByUser(paramUser);
System.out.println("练习使用 resultType, user= " + user);
}
where的使用
他会自己判断后面有没有语句。并且判断是否添加and
<select id="selectUserByUsernamePasswordForWhere" resultType="com.example.demomybatis.pojo.User">
select * from tb_user
<where>
<if test="username != null">
and username = #{username}
</if>
<if test="password != null">
and password=#{password}
</if>
</where>
@Test
public void testSelectUserByUsernamePasswordForWhere(){
String userName = "123";
String password = "123";
// List users = userMapper.selectUserByUsernamePasswordForWhere(userName, password);
//select * from tb_user where username=? and password=?
// List users = userMapper.selectUserByUsernamePasswordForWhere(null, password);
//select * from tb_user WHERE password=?
//List users = userMapper.selectUserByUsernamePasswordForWhere(userName, null);
//select * from tb_user WHERE username = ?
List<User> users = userMapper.selectUserByUsernamePasswordForWhere(null, null);
// select * from tb_user
System.out.println(users);
}
update
- 自动在要修改的第一个字段之前添加
SET关键字 - 去掉最后一个要修改字段后的连接符( , )。
<update id="updateUser" parameterType="User">
update `tb_user`
<set>
`username` = #{username},
<if test="password!=null">
password=#{password}
</if>
</set>
where `id` = #{id}
</update>
trim
mybatis的trim标签一般用于去除sql语句中多余的and关键字，逗号，或者给sql语句前拼接 “where“、“set“以及“values(“ 等前缀，或者添加“)“等后缀，可用于选择性插入、更新、删除或者条件查询等操作。
<select id="selectUserByUsernamePasswordForTrim" resultType="com.example.demomybatis.pojo.User">
select * from tb_user
<trim prefix="where" prefixOverrides="and|or">
<if test="username!=null">
and username=#{username}
</if>
<if test="password!=null">
and password=#{password}
</if>
</trim>
</select>
<update id="updateUserForTrim" parameterType="User">
update `tb_user`
<trim prefix="SET" suffixOverrides=",">
`username`=#{username},
<if test="password!=null">
password=#{password}
</if>
</trim>
where `id`=#{id}
</update>
根据数组查询
<!--根绝数组查询多个用户记录-->
<select id="selectByIds" resultType="com.example.demomybatis.pojo.User">
select * from tb_user where id
<foreach collection="ids" item="id" open="in(" separator="," close=")">
#{id}
</foreach>
</select>
批量插入：
<insert id="batchInsert">
insert into `tb_user`
(`username`,
`password`,
`age`,
`phone`,
`email`,
`gmt_create`,
`login_time`)
VALUES
<foreach collection="list" item="user" open="(" separator="),(" close=")">
#{user.username}, #{user.password}, #{user.age}, #{user.phone}, 'eamil', null,null
</foreach>
</insert>
代码复用
<!--公共代码部分-->
<sql id="selectUserAll">
select `id`, `username`,`password`,`age`,`phone`,`email`,`gmt_create`,`login_time` from tb_user
</sql>
引用：
<select id="selectListByCondition" resultType="com.example.demomybatis.pojo.User">
<include refid="selectUserAll"></include>
where username like concat('%', #{username}, '%')
</select>
DAY10
缓存
加快访问速度
DAY11
项目结构：
Controller
package cn.niit.hospital.controller;
import cn.niit.hospital.entity.domain.User;
import cn.niit.hospital.service.UserService;
import lombok.extern.slf4j.Slf4j;
import org.apache.ibatis.annotations.Delete;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.ArrayList;
import java.util.List;
/**
* @Description: 用户控制器
* @Author: tang_meng
* @CreateTime： 2023/3/16 16:23
*/
@RestController
@Slf4j
public class UserController {
@Autowired
private UserService userService;
/**
* @Description: 接口一， 根据某个id查询用户
* @Author: tang_meng
* @CreateTime: 2023/3/20 8:39
* @param: id
* @return: cn.niit.hospital.entity.domain.User
**/
@RequestMapping("/user/{id}")
public User getById(@PathVariable("id") Long id){
User user = userService.getUserById(id);
return user;
}
/**
* @Description: 接口二： 查询用户列表接口
* @Author: tang_meng
* @CreateTime: 2023/3/20 8:42
* @param: 封装着查询（多个）条件的用户对象
* @return: java.util.List
**/
@GetMapping("/user")
public List<User> list(User user){
log.info("接受得到的参数 {} "+user);
List<User> users = userService.getListByUser(user);
return users;
}
/**
* @Description: 接口三： 新增接口
* @Author: tang_meng
* @CreateTime: 2023/3/20 8:44
* @return: java.lang.String
**/
@PostMapping("/user")
public Integer add(@RequestBody User user){
log.info("接收到的参数： {} "+user);
int rows = userService.addUser(user);
return rows;
}
/**
* @Description: 接口四： 更新接口
* @Author: tang_meng
* @CreateTime: 2023/3/20 8:45
* @param: user
* @return: java.lang.String
**/
@PutMapping("/user")
public String update(User user){
log.info("接收到的参数： {} "+user);
int rows = userService.updateUser(user);
if(rows == 1)
return "更新成功";
else return "更新失败！";
}
// @RequestMapping(value = "/user/{id}", method = RequestMethod.DELETE)
@DeleteMapping("/user/{id}") //和上面等价，推荐这个
public String delete(@PathVariable("id") Long id){
int rows = userService.deleteUser(id);
return "ol";
}
}
UserServiceImpl
package cn.niit.hospital.service.impl;
import cn.niit.hospital.entity.domain.User;
import cn.niit.hospital.mapper.UserMapper;
import cn.niit.hospital.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
/**
* @Description: 用户服务实现类
* @Author: tang_meng
* @CreateTime： 2023/3/17 9:08
*/
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserMapper userMapper;
/**
* @Description: 查询用户根据ID
* @Author: tang_meng
* @CreateTime: 2023/3/17 9:22
* @param: id
* @return: cn.niit.hospital.entity.domain.User
**/
@Override
public User getUserById(Long id) {
return userMapper.getUserById(id);
}
/**
* @Description: 根据封装条件查看用户列表
* @Author: tang_meng
* @CreateTime: 2023/3/20 9:36
* @param: user
* @return: java.util.List
**/
@Override
public List<User> getListByUser(User user) {
return userMapper.selectListByUser(user);
}
/**
* @Description: 添加用户
* @Author: tang_meng
* @CreateTime: 2023/3/20 10:55
* @param: user
* @return: int
**/
@Override
public int addUser(User user) {
user.setStatus(0);
user.setDelFlag(0);
user.setCreateUserId(0L);
user.setCreateUserName("系统管理员");
return userMapper.insertUser(user);
}
@Override
public int updateUser(User user) {
user.setCreateUserId(0L);
user.setCreateUserName("系统管理员");
return userMapper.updateUser(user);
}
@Override
public int deleteUser(Long id) {
// return userMapper.deleteUserById(id); 物理删除
User user=new User();
user.setId(id);
user.setDelFlag(1);
user.setUpdateUserId(1L);
user.setUpdateUserName("超级系统管理员");
return userMapper.deleteByUser(user); //逻辑删除
}
}
UserMapper.xml
<?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">
<!-- namespace 将 XxxMapper.java 接口类与 XxxMapper.xml 做映射 -->
<mapper namespace="cn.niit.hospital.mapper.UserMapper">
<sql id="selectAllSQL">
SELECT
`id`,
`phone`,
`id_card`,
`user_name`,
`password`,
`birthday`,
`sex`,
`status`,
`del_flag`,
`create_user_id`,
`create_user_name`,
`gmt_create`,
`update_user_id`,
`update_user_name`,
`gmt_update`
</sql>
<insert id="insertUser">
INSERT INTO `tb_userone`
(`phone`,
`id_card`,
`user_name`,
`password`,
`birthday`,
`sex`,
`status`,
`del_flag`,
`create_user_id`,
`create_user_name`,
`gmt_create`)
VALUES (#{phone},
#{idCard},
#{userName},
#{password},
#{birthday},
#{sex},
#{status},
#{delFlag},
#{createUserId},
#{createUserName},
now() );
</insert>
<update id="updateUser">
update `tb_userone`
set `phone` = #{phone},
`id_card` = #{idCard},
`user_name` = #{userName},
`password` = #{password},
`birthday` = #{birthday},
`sex` = #{sex},
`update_user_id` = #{updateUserId},
`update_user_name` = #{updateUserName},
`gmt_update` = now()
where `id` = #{id}
</update>
<delete id="deleteUserById">
delete from `tb_userone` where `id`=#{id}
</delete>
<update id="deleteByUser">
update `tb_userone`
set `del_flag` = #{delFlag},
`update_user_id` = #{updateUserId},
`update_user_name` = #{updateUserName},
`gmt_update` = now()
where `id` = #{id}
</update>
<select id="selectListByUser" resultType="cn.niit.hospital.entity.domain.User">
<include refid="selectAllSQL"></include>
from tb_userone
<where>
<if test="phone!=null and phone !=''">
and phone = #{phone}
</if>
<if test="userName!=null and userName!=''">
and user_name like '%' #{userName} '%'
</if>
</where>
</select>
<select id="getUserById" resultType="cn.niit.hospital.entity.domain.User">
select * from tb_user where id = #{id}
</select>
</mapper>