REST处理错误的参数

Question

在RESTful服务中处理错误参数的正确方法是什么？我现在有一个端点，如果发送错误的数据类型，它将返回400。

@ResponseBody 
@RequestMapping(produces = "application/json", method = RequestMethod.GET, value="/v1/test") 
public MyResponse getSomething(@RequestParam BigDecimal bd) { 
    MyResponse r = new MyResponse(); 
    r.setBd(bd); 
    return r; 
} 

这将是非常好的，如果最终用户都通过，比方说，一个字符串，而不是一个BigDecimal，该响应将返回一个JSON的响应代码，状态，和其他任何我想它包含，而不仅仅是400.有没有办法做到这一点？

更新：我最初的想法是包装每个参数，然后检查它是否是包装类中的正确类型。这似乎有点愚蠢。是不是有一个验证程序，我可以添加到类路径，可以识别这样的事情？

另外，有一种方法可以很容易地用我自己创建的Bean类型来处理，但是像BigDecimal这样的标准类型呢？

UPDATE-2：此更新解决了使用@ExceptionHandler的答案。

TestController.java

import java.math.BigDecimal; 
import javax.servlet.http.HttpServletRequest; 
import org.springframework.stereotype.Controller; 
import org.springframework.web.bind.ServletRequestBindingException; 
import org.springframework.web.bind.annotation.ExceptionHandler; 
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; 

@Controller 
@RequestMapping("/") 
public class TestController { 

    //this is where correct input from user is passed, no binding errors 
    @RequestMapping(produces = "application/json", method = RequestMethod.GET, value="/v1/test") 
    public 
    @ResponseBody 
    MyResponse getSomething(@RequestParam BigDecimal bd) { 
     MyResponse r = new MyResponse(); 
     r.setBd(bd); 
     return r; 
    } 

    //this will handle situation when you except number and user passess string (A123.00 for example) 
    @ExceptionHandler(ServletRequestBindingException.class) 
    public @ResponseBody MyErrorResponse handleMyException(Exception exception, HttpServletRequest request) { 

     MyErrorResponse r = new MyErrorResponse(); 
     r.setEexception(exception); 

     return r; 
    } 


} 

TestUnitTest.java

public class TestUnitTest { 

protected MockMvc mockMvc; 

@Autowired 
protected WebApplicationContext wac; 

@Before 
public void setup() { 
    this.mockMvc = MockMvcBuilders.webAppContextSetup(this.wac).build(); 
} 


@Test 
public void test() throws Exception { 
    String url = "/v1/test?bd=a123.00"; 

    log.info("Testing Endpoint::: " + url); 

    MvcResult result = mockMvc.perform(get(url)) 
         .andExpect(status().isOk()) 
         .andReturn(); 

    log.info("RESPONSE::: " + result.getResponse().getContentAsString()); 
} 

} 

MyResponse.java

import java.math.BigDecimal; 

public class MyResponse { 

    private BigDecimal bd; 

    public BigDecimal getBd() { 
     return bd; 
    } 

    public void setBd(BigDecimal bd) { 
     this.bd = bd; 
    } 

} 

MyErrorResponse.java

public class MyErrorResponse { 

    private Exception exception; 

    public Exception getException() { 
     return exception; 
    } 

    public void setEexception(Exception e) { 
     this.exception = e; 
    } 

} 

Answer 1

使用Spring @ExceptionHandler标准@RequestMapping注释这样一起：

//this is where correct input from user is passed, no binding errors 
@RequestMapping(produces = "application/json", method = RequestMethod.GET, value="/v1/test") 
public 
@ResponseBody 
MyResponse getSomething(@RequestParam BigDecimal bd) { 
    MyResponse r = new MyResponse(); 
    r.setBd(bd); 
    return r; 
} 

//this will handle situation when there's exception during binding, for example you except number and user passess string (A123.00 for example) 
@ExceptionHandler(TypeMismatchException.class) 
public 
@ResponseBody 
MyErrorResponse handleMyException(Exception exception, HttpServletRequest request) { 
    //.... 
} 

TypeMismatchException是试图建立一个bean的属性时抛出的一般例外。你可以概括的代码，甚至更多，抓住每一个结合异常有一些方法，例如：

@ExceptionHandler(TypeMismatchException.class) 
public 
@ResponseBody 
String typeMismatchExpcetionHandler(Exception exception, HttpServletRequest request) { 
    return "type mismatch"; 
} 

@ExceptionHandler(MissingServletRequestParameterException.class) 
public 
@ResponseBody 
String missingParameterExceptionHandler(Exception exception, HttpServletRequest request) { 
    return "missing param"; 
} 

@ExceptionHandler(Exception.class) 
public 
@ResponseBody 
String generalExceptionHandler(Exception exception, HttpServletRequest request) { 
    return "general exception"; 
} 

这是非常灵活的，允许在签名许多参数和返回的对象Annotation Type ExceptionHandler

随着@ResponseBody你可以返回任何对象，可以序列化为JSON。它只需要在你的类路径中有杰克森库，但我认为你已经知道这个