我们先来说说问问的所在
Rest 接口中的异常,如何能在RestTemplate 中显示出来.RestTemplate 中try catch 的 e.getMessage()只能是请求本身代码异常.(400 null 或者 500 null),但是 用postman 调用的时候是可以显示错误信息的.这是怎么回事?
问题代码
- Rest 接口
@PostMapping("/test")
public ResponseEntity save(@RequestBody List vos){
System.out.println(JSON.toJSONString(vos));
// return new ResponseEntity("fuck you ", HttpStatus.BAD_GATEWAY) ;
// return new ResponseEntity("fuck you ", HttpStatus.OK) ; //只有ok 能走通
return new ResponseEntity("fuck you ", HttpStatus.NOT_FOUND) ;
- RestTemplate调用
RestTemplate restTemplate = new RestTemplate();
List vos = new ArrayList<>();
try {
ResponseEntity responseEntity = restTemplate.postForEntity("url",vos, Object.class);
}catch (Exception e) {
e.printStackTrace();
System.out.println(e.getMessage());
}
说明try catch 只能获取restTemplate本事是否调取成功,不成功则异常.
##寻求解决办法
restTemplate 对错误处理有个方法,从中获取到response ,从response中获取body即可,说的容易,来看代码
- RestTemplate调用
RestTemplate restTemplate = new RestTemplate();
List vos = new ArrayList<>();
try {
// 错误处理
restTemplate.setErrorHandler(new CustomResponseErrorHandler());
ResponseEntity responseEntity = restTemplate.postForEntity("/test",vos, Object.class);
}catch (CustomException e) {
e.printStackTrace();
System.out.println(e.getBody());
System.out.println(e.getMessage());
}
- CustomResponseErrorHandler 错误处理类
public class CustomResponseErrorHandler implements ResponseErrorHandler {
private ResponseErrorHandler errorHandler = new DefaultResponseErrorHandler();
@Override
public void handleError(ClientHttpResponse response) throws IOException {
// 队请求头的处理
List customHeader = response.getHeaders().get("x-app-err-id");
String svcErrorMessageID = "";
if (customHeader != null) {
svcErrorMessageID = customHeader.get(0);
}
//对body 的处理 (inputStream)
String body = convertStreamToString(response.getBody());
try {
errorHandler.handleError(response);
} catch (RestClientException scx) {
throw new CustomException(scx.getMessage(), scx, body);
}
}
@Override
public boolean hasError(ClientHttpResponse response) throws IOException {
return errorHandler.hasError(response);
}
// inputStream 装换为 string
private String convertStreamToString(InputStream is) {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
}
- 自定义异常捕获的类
public class CustomException extends RestClientException {
private RestClientException restClientException;
private String body;
public RestClientException getRestClientException() {
return restClientException;
}
public void setRestClientException(RestClientException restClientException) {
this.restClientException = restClientException;
}
public String getBody() {
return body;
}
public void setBody(String body) {
this.body = body;
}
public CustomException(String msg, RestClientException restClientException, String body) {
super(msg);
this.restClientException = restClientException;
this.body = body;
}
}
大功告成
总结下
主要就是这个restTemplate 没有对错误请求做处理,只有正确请求.所以需要手动增加
setErrorHandler方法处理.
可参考：
- https://stackoverflow.com/questions/7878002/resttemplate-handling-response-headers-body-in-exceptions-restclientexception
- http://www.developerq.com/article/1504414182
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