SpringBoot数据访问操作
完成 SpringBoot 与 Mybatis 集成后，接下来以学生表为例实现一套用户模块基本数据维护。
查询操作
接口方法定义
package com.xxxx.springboot.dao;
import com.xxxx.springboot.po.User;
public interface UserDao {
//查询操作
//通过id查询用户对象
public User queryUserById(Integer id);
}
映射文件配置
<?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.xxxx.springboot.dao.UserDao">
<!--查询操作-->
<select id="queryUserById" parameterType="int" resultType="com.xxxx.springboot.po.User">
select * from student where user_id = #{id}
</select>
</mapper>
UserService
package com.xxxx.springboot.service;
import com.xxxx.springboot.dao.UserDao;
import com.xxxx.springboot.po.User;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
@Service
public class UserService {
@Resource
private UserDao userDao;
/**
* 通过id查询用户对象
* @param id
* @return
*/
public User queryUserById(Integer id){
return userDao.queryUserById(id);
}
}
UserController
package com.xxxx.springboot.controller;
import com.xxxx.springboot.po.User;
import com.xxxx.springboot.service.UserService;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
@RestController
public class UserController {
@Resource
private UserService userService;
/**
* 查询操作
* 通过id查询用户对象
* @param id
* @return
*/
@GetMapping("user/id/{id}")
public User queryUserByName(@PathVariable Integer id){
User user = userService.queryUserById(id);
return user;
}
}
添加操作
接口方法定义
package com.xxxx.springboot.dao;
import com.xxxx.springboot.po.User;
public interface UserDao {
//添加操作
public int addUser(User user);
}
映射文件配置
<?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.xxxx.springboot.dao.UserDao">
<!--添加操作-->
<insert id="addUser" parameterType="com.xxxx.springboot.po.User">
insert into
student
(user_name,user_email,user_age)
values
(#{userName},#{userEmail},#{userAge})
</insert>
</mapper>
添加 commons-lang3 依赖
如果需要使用 StringUtils 工具类，需要引入 commons-lang3 依赖。
<!-- commons-lang3 -->
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
</dependency>
ParamsException 自定义异常
package com.xxxx.springboot.exception;
/**
* 自定义异常
* 参数异常
*/
public class ParamsException extends RuntimeException{
private Integer code = 300;
private String msg = "参数异常!";
public ParamsException() {
super("参数异常!");
}
public ParamsException(String msg) {
super(msg);
this.msg = msg;
}
public ParamsException(Integer code) {
super("参数异常!");
this.code = code;
}
public ParamsException(Integer code, String msg) {
super(msg);
this.code = code;
this.msg = msg;
}
public Integer getCode() {
return code;
}
public void setCode(Integer code) {
this.code = code;
}
public String getMsg() {
return msg;
}
public void setMsg(String msg) {
this.msg = msg;
}
}
AssertUtil 工具类
package com.xxxx.springboot.utils;
import com.xxxx.springboot.exception.ParamsException;
/**
* 工具类
*/
public class AssertUtil {
/**
* 判断返回值
* @param flag
* @param mag
*/
public static void isTrue(boolean flag,String mag){
//如果为true，则抛出异常
if(flag){
throw new ParamsException(mag);
}
}
}
UserService
package com.xxxx.springboot.service;
import com.xxxx.springboot.dao.UserDao;
import com.xxxx.springboot.po.User;
import com.xxxx.springboot.utils.AssertUtil;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
@Service
public class UserService {
@Resource
private UserDao userDao;
/**
* 添加用户
* 1.非空校验
* 2.用户名唯一
* 3.添加用户记录，判断受影响行数
* @param user
*/
public void addUser(User user){
//非空校验
AssertUtil.isTrue(StringUtils.isBlank(user.getUserName()),"用户名不能为空！");
AssertUtil.isTrue(StringUtils.isBlank(user.getUserEmail()),"用户邮箱不能为空！");
AssertUtil.isTrue(StringUtils.isBlank(user.getUserAge()),"用户年龄不能为空！");
//验证用户名的唯一性
User temp = userDao.queryUserByName(user.getUserName());
//判断指定用户名查询的用户对象是否存在
AssertUtil.isTrue(null != temp ,"用户名已存在！");
//添加用户记录，判断受影响行数
AssertUtil.isTrue(userDao.addUser(user)<1,"用户添加失败！");
}
}
ResultInfo
package com.xxxx.springboot.po;
public class ResultInfo {
private Integer code = 200;
private String msg = "操作成功";
private Object result;
public Integer getCode() {
return code;
}
public void setCode(Integer code) {
this.code = code;
}
public String getMsg() {
return msg;
}
public void setMsg(String msg) {
this.msg = msg;
}
public Object getResult() {
return result;
}
public void setResult(Object result) {
this.result = result;
}
}
UserController
package com.xxxx.springboot.controller;
import com.xxxx.springboot.exception.ParamsException;
import com.xxxx.springboot.po.ResultInfo;
import com.xxxx.springboot.po.User;
import com.xxxx.springboot.service.UserService;
import org.springframework.web.bind.annotation.*;
import javax.annotation.Resource;
@RestController
public class UserController {
@Resource
private UserService userService;
/**
* 添加用户
* @param user
* @return
*/
@PostMapping("user/add")
public ResultInfo addUser(@RequestBody User user){
ResultInfo resultInfo = new ResultInfo();
try{
userService.addUser(user);
}catch (ParamsException p){
resultInfo.setCode(p.getCode());
resultInfo.setMsg(p.getMsg());
p.printStackTrace();
}catch (Exception e){
e.printStackTrace();
resultInfo.setCode(500);
resultInfo.setMsg("用户添加失败");
}
return resultInfo;
}
}