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
@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、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")
@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;
}
}
代码
参考
Bean Validation 技术规范特性概述
Validation, Data Binding, and Type Conversion
