Spring校验@RequestParams和@PathVariables参数

我们在写Rest API接口时候会用到很多的@RequestParam和@PathVariable进行参数的传递，但是在校验的时候，不像使用@RequestBody那样的直接写在实体类中，我们这篇文章讲解一下如何去校验这些参数。依赖配置要使用Java Validation API，我们必须添加validation-api依赖项：<dependency> <groupId>javax.validation</groupId> <artifactId>validation-api</artifactId> <version>2.0.1.Final</version></dependency>通过添加@Validated注解来启用控制器中的@RequestParams和@PathVariables的验证：@RestController@RequestMapping("/")@Validatedpublic class Controller { // …}校验@RequestParam我们将数字作为请求参数传递给控制器方法@GetMapping("/name-for-day")public String getNameOfDayByNumber(@RequestParam Integer dayOfWeek) { // …}我们保证dayOfWeek的值在1到7之间，我们使用@Min和@Max注解@GetMapping("/name-for-day")public String getNameOfDayByNumber(@RequestParam @Min(1) @Max(7) Integer dayOfWeek) { // …}任何与这些条件不匹配的请求都将返回HTTP状态500，并显示默认错误消息。如果我们尝试调用http://localhost:8080/name-for-day?dayOfWeek=24这将返回以下响应信息：There was an unexpected error (type=Internal Server Error, status=500).getNameOfDayByNumber.dayOfWeek: must be less than or equal to 7当然我们也可以在@Min和@Max注解后面加上message参数进行修改默认的返回信息。校验@PathVariable和校验@RequestParam一样，我们可以使用javax.validation.constraints包中的注解来验证@PathVariable。验证String参数不是空且长度小于或等于10@GetMapping("/valid-name/{name}")public void test(@PathVariable(“name”) @NotBlank @Size(max = 10) String username) { // …}任何名称参数超过10个字符的请求都会导致以下错误消息：There was an unexpected error (type=Internal Server Error, status=500).createUser.name:size must be between 0 and 10通过在@Size注解中设置message参数，可以覆盖默认消息。其实我们可以看到校验@RequestParam和@PathVariable参数和我们校验@RequestBody方式一致，只不过一个是写在了实体中，一个写在了外部，当然我们也可以将@RequestParam的参数写入到实体类中，进行使用@RequestParam注解进行引入，比如我们使用一个分页的实例分页实体类/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * “License”); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an “AS IS” BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. /package com.zhuanqb.param.page;import lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor;import lombok.ToString;import org.hibernate.validator.constraints.NotBlank;import org.hibernate.validator.constraints.NotEmpty;import javax.validation.constraints.Max;import javax.validation.constraints.Min;import javax.validation.constraints.NotNull;/* * PageParam * 描述 : PageParam * 作者 : qianmoQ * 版本 : 1.0 * 创建时间 : 2018-09-23 下午7:40 * 联系作者 : <a href=“mailTo:shichengoooo@163.com”>qianmoQ</a> */@Data@ToString@NoArgsConstructor@AllArgsConstructorpublic class PageParam { @NotNull(message = “每页数据显示数量不能为空”) @Min(value = 5) @Max(value = 100) private Integer size; // 每页数量 @NotNull(message = “当前页显示数量不能为空”) @Min(value = 1) @Max(value = Integer.MAX_VALUE) private Integer page; // 当前页数 private Boolean flag = true;}@RequestParam调用方式 @GetMapping(value = “list”) public CommonResponseModel findAll(@Validated PageParam param) { … }这样的话可以使我们的校验定制化更加简单。