概述

Spring MVC支持Bean Validation，通過這個(gè)驗(yàn)證技術(shù)，可以通過注解方式，很方便的對(duì)輸入?yún)?shù)進(jìn)行驗(yàn)證，之前使用的校驗(yàn)方式，都是基于Bean對(duì)象的，但是在@RequestParam中，沒有Bean對(duì)象，這樣使得校驗(yàn)無法進(jìn)行，可以通過使用@Validated注解，使得校驗(yàn)可以進(jìn)行。

校驗(yàn)bean對(duì)象

一般校驗(yàn)bean對(duì)象，為了可以自動(dòng)的校驗(yàn)屬性，可以通過兩步解決：

一、聲明對(duì)象

package com.github.yongzhizhan.draftbox.model;

import javax.validation.constraints.Size;

/**
 * 帶驗(yàn)證的對(duì)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、通過@Valid注解使用對(duì)象

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

    return vFoo.getValidString();
}

校驗(yàn)RequestParams

使用校驗(yàn)bean的方式，沒有辦法校驗(yàn)RequestParam的內(nèi)容，一般在處理Get請(qǐng)求的時(shí)候，會(huì)使用下面這樣的代碼：

@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，對(duì)RequestParam對(duì)應(yīng)的參數(shù)進(jìn)行注解，是無效的，需要使用@Validated注解來使得驗(yàn)證生效。操作步驟如下：

一、聲明錯(cuò)誤處理類

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
@Component
public 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、聲明@Validated并加上校驗(yàn)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")
@Validated
public 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;
    }
}

代碼

在github中查看完整代碼

參考

Bean Validation 技術(shù)規(guī)范特性概述
Validation, Data Binding, and Type Conversion