概述

  Spring MVC支持Bean Validation，通过这个验证技术，可以通过注解方式，很方便的对输入参数进行验证，之前使用的校验方式，都是基于Bean对象的，但是在@RequestParam中，没有Bean对象，这样使得校验无法进行，可以通过使用@Validated注解，使得校验可以进行。

校验bean对象

  一般校验bean对象，为了可以自动的校验属性，可以通过两步解决：

一、声明对象

package com.github.yongzhizhan.draftbox.model;import javax.validation.constraints.Size;/** * 带验证的对象 * @author zhanyongzhi */public class Foo {    private String validString;    @Size(min = 1, max = 5)    public String getValidString() {        return validString;    }    public void setValidString(final String vValidString) {        validString = vValidString;    }}

二、通过@Valid注解使用对象

@ResponseBody@RequestMapping(value = "validObject", method = RequestMethod.POST)@ResponseStatus(HttpStatus.OK)public String validObject(        @RequestBody()        @Valid Foo vFoo, BindingResult vBindingResult){    return vFoo.getValidString();}

校验RequestParams

  使用校验bean的方式，没有办法校验RequestParam的内容，一般在处理Get请求的时候，会使用下面这样的代码：

@ResponseBody@RequestMapping(value = "validString", method = RequestMethod.GET)@ResponseStatus(HttpStatus.OK)public String validString(        @RequestParam(value = "str", defaultValue = "")        String vStr){    return vStr;}

  使用@Valid注解，对RequestParam对应的参数进行注解，是无效的，需要使用@Validated注解来使得验证生效。操作步骤如下：

一、声明错误处理类

package com.github.yongzhizhan.draftbox.controller;import org.springframework.context.annotation.Bean;import org.springframework.http.HttpStatus;import org.springframework.stereotype.Component;import org.springframework.validation.beanvalidation.MethodValidationPostProcessor;import org.springframework.web.bind.annotation.ControllerAdvice;import org.springframework.web.bind.annotation.ExceptionHandler;import org.springframework.web.bind.annotation.ResponseBody;import org.springframework.web.bind.annotation.ResponseStatus;import javax.validation.ValidationException;@ControllerAdvice@Componentpublic class GlobalExceptionHandler {    @Bean    public MethodValidationPostProcessor methodValidationPostProcessor() {        return new MethodValidationPostProcessor();    }    @ExceptionHandler    @ResponseBody    @ResponseStatus(HttpStatus.BAD_REQUEST)    public String handle(ValidationException exception) {        System.out.println("bad request, " + exception.getMessage());        return "bad request, " + exception.getMessage();    }}

二、声明@Validated并加上校验注解

package com.github.yongzhizhan.draftbox.controller;import com.github.yongzhizhan.draftbox.model.Foo;import org.springframework.beans.factory.annotation.Value;import org.springframework.http.HttpStatus;import org.springframework.validation.BindingResult;import org.springframework.validation.annotation.Validated;import org.springframework.web.bind.annotation.RequestBody;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.ResponseBody;import org.springframework.web.bind.annotation.ResponseStatus;import org.springframework.web.bind.annotation.RestController;import javax.validation.Valid;import javax.validation.constraints.Size;@RestController@SuppressWarnings("UnusedDeclaration")@Validatedpublic class IndexController {    @ResponseBody    @RequestMapping(value = "validString", method = RequestMethod.GET)    @ResponseStatus(HttpStatus.OK)    public String validString(            @RequestParam(value = "str", defaultValue = "")            @Size(min = 1, max = 3)            String vStr){        return vStr;    }}

代码

参考