Spring中使用JSR303請求約束判空的實現
阿新 • • 發佈：2020-12-21
1. 適用場景
有時候我們在表單裡提交一系列引數,到後臺封裝成一個物件,要對物件的屬性做各種欄位值的約束; 這時候,當然可以if-else一個一個的判斷,有更簡潔的做法,就是使用 JSR303+spring的validation:
2. 使用方法步驟(分3步)
- 實體類加欄位約束註解
- Controller類中@Valid標註啟用(@Validated也相容@Valid)
- BindingResult獲取報錯資訊
2.1 實體類加欄位約束註解
如我們要收集前端表單的欄位資料到Person實體中:
對需要約束的欄位進行註解標註;
示例:
2.1.1 Person.java
package com.niewj.demo.model;
import lombok.Data;
import org.hibernate.validator.constraints.Length;
import org.hibernate.validator.constraints.URL;
import javax.validation.constraints.*;
import java.util.List;
@Data
public class Person {
@Length(min = 4,max = 10)
@NotNull(message = "name不能為空")
private String name;
@Min(0)
@Max(40)
@NotNull(message = "age不能為空")
private Integer age;
@NotBlank
@NotBlank
@URL(message = "logo必須是URL格式")
private String logo;
@NotEmpty(message = "hobbies不能為空")
private List<String> hobbies;
@Email
@NotNull(message = "email不能為空!")
private String mail;
}@NotNull 約束欄位不可為空;
@NotEmpty 約束集合/map等不能為空不能為0元素
@Email 約束是 email格式
@URL 約束必須是url的格式
message屬性可以修改預設錯誤說明
2.2 Controller類中@Valid標註啟用(@Validated相容@Valid)
2.2.1 HelloController.java
package com.niewj.demo.controller;
import com.google.gson.Gson;
import com.niewj.demo.common.Result;
import com.niewj.demo.model.Person;
import com.niewj.demo.service.TestService1;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.*;
import javax.annotation.Resource;
import javax.validation.Valid;
import java.util.HashMap;
import java.util.Map;
/**
* test
*
* @author niewj
* @since 2020/11/16 15:22
*/
@Controller
public class HelloController {
/**
* @param person
* @param bindingResult
* @return
*/
@PostMapping("/test")
@ResponseBody
public Result doSth(@Valid @RequestBody Person person,BindingResult bindingResult) {
Map<String,String> map = new HashMap<>();
if (bindingResult.hasErrors()) {
bindingResult.getFieldErrors().stream().forEach(fe-> map.put(fe.getField(),fe.getDefaultMessage()));
System.out.println(bindingResult.getFieldError().getDefaultMessage());
return Result.withErrorParamData(map);
}
return Result.withSuccessData(person);
}
}
@RequestBody可以將body中的請求流資訊(Request.getInputStream)通過HttpMessageConverter自動轉換為目標java型別:
- 如果前端 Content-Type為application/json,就使用 JSON訊息轉換器 幫你轉為JSON物件;
- 如果前端 Content-Type為application/xml,就使用 XML訊息轉換器 幫你轉為xml;
- 如果前端 Content-Type為text/plain,就是用 String訊息轉換器 幫你轉成 String; (只有型別為String時才可以轉換)
2.2.2 Result.java:
package com.niewj.demo.common;
import lombok.Data;
import java.io.Serializable;
import java.util.Map;
/**
* 返回結果模板封裝
*
* @author niewj
* @since 2020/12/17 18:05
*/
@Data
public class Result<T> implements Serializable {
private int code;
private String msg;
private T data;
public Result(int code,String msg,T data) {
this(code,msg);
this.data = data;
}
public Result(int code,String msg) {
this.msg = msg;
this.code = code;
}
public static <T> Result<T> withData(ResponseEnum responseCode,T data) {
Result<T> re = new Result(responseCode.getCode(),responseCode.getMsg());
re.data = data;
return re;
}
public static Result<String> withSuccessNoData() {
Result re = new Result(ResponseEnum.SUCCESS.getCode(),ResponseEnum.SUCCESS.getMsg());
re.data = "";
return re;
}
public static <T> Result<T> withSuccessData(T data) {
Result re = new Result(ResponseEnum.SUCCESS.getCode(),ResponseEnum.SUCCESS.getMsg());
re.data = data;
return re;
}
public static Result<Map<String,String>> withErrorParamData(Map<String,String> data) {
Result re = new Result(ResponseEnum.BAD_REQUEST.getCode(),ResponseEnum.BAD_REQUEST.getMsg());
re.data = data;
return re;
}
}
2.2.3 ResponseEnum.java
package com.niewj.demo.common;
/**
* 通用響應碼
*/
public enum ResponseEnum {
SUCCESS(200,"成功"),BAD_REQUEST(400,"請求引數不合規");
/**
* 錯誤碼
*/
private Integer code;
/**
* 錯誤資訊
*/
private String msg;
ResponseEnum(Integer code,String msg) {
this.code = code;
this.msg = msg;
}
public String getMsg() {
return msg;
}
public Integer getCode() {
return code;
}
}
2.3 BindingResult獲取報錯資訊
- BindingResult用來收集約束欄位的錯誤資訊,可通過 bindingResult.hasErrors()的 true來過濾錯誤資訊;
- bindingResult.getFieldErrors() 會返回 List<FieldError>;
- FieldError 得到欄位名: getField(); 得到錯誤資訊: getDefaultMessage()
3. 呼叫測試:
http://localhost:8888/test
3.1 請求用例1: 欄位為空
header: Content-Type: application/json
{
"name": "1"
}
響應:
{
"code": 400,"msg": "請求引數不合規","data": {
"mail": "email不能為空!","hobbies": "hobbies不能為空","name": "長度需要在4和10之間","logo": "不能為空","age": "age不能為空"
}
}
3.2 請求用例2: list無元素/email/url格式不對
header: Content-Type: application/json
{
"name": "1234","hobbies": [],"mail": "niewj","logo": "niewj.com"
}
響應:
{
"code": 400,"data": {
"mail": "不是一個合法的電子郵件地址","logo": "logo必須是URL格式","age": "age不能為空"
}
}
3.3 請求用例3: 完整欄位資訊
header: Content-Type: application/json
{
"name": "1234","hobbies": ["running"],"mail": "[email protected]","logo": "http://niewj.com","age": 40
}
響應:
{
"code": 200,"msg": "成功","data": {
"name": "1234","age": 40,"hobbies": [
"running"
],"mail": "[email protected]"
}
}
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