记录 RestTemplate 生成的异常时如何打印完整的错误消息？

Question

我们有一个基于 Spring-Boot (2.3.10.RELEASE) 的应用程序，它使用 RestTemplate 调用许多 REST API。

如果任何 REST API 返回任何 4xx 或 5xx HTTP 错误代码以及消息正文，则不会记录完整的消息正文。

这是一个最小的可重现示例：

import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.springframework.web.client.HttpClientErrorException;
import org.springframework.web.client.RestTemplate;

@Slf4j
public class RestTemplateTest {

    @Test
    void shouldPrintErrorForRestTemplate() {
        RestTemplate restTemplate = new RestTemplate();
        try {
            restTemplate.getForEntity("http://hellosmilep.free.beeceptor.com/error/notfound", String.class);
        } catch (Exception e) {
            log.error("Error calling REST API", e);
        }
    }
}

输出：

10:28:11.347 [main] ERROR com.smilep.java.webapp.RestTemplateTest - Error calling REST API
org.springframework.web.client.HttpClientErrorException$NotFound: 404 Not Found: [{
  "glossary": {
    "title": "example glossary",
    "GlossDiv": {
      "title": "S",
      "GlossList": {
        "GlossEntry": {
          "ID": "SGML",
          "SortAs": "SGML",
          "Glo... (593 bytes)]
    at org.springframework.web.client.HttpClientErrorException.create(HttpClientErrorException.java:113)
    at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:184)
    at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:125)
    at org.springframework.web.client.ResponseErrorHandler.handleError(ResponseErrorHandler.java:63)
    at org.springframework.web.client.RestTemplate.handleResponse(RestTemplate.java:780)
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:738)
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:672)
    at org.springframework.web.client.RestTemplate.getForEntity(RestTemplate.java:340)
    at com.smilep.java.webapp.RestTemplateTest.shouldPrintErrorForRestTemplate(RestTemplateTest.java:15)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:686)
    at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)
    at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:149)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:140)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:84)
    at org.junit.jupiter.engine.execution.ExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(ExecutableInvoker.java:115)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.lambda$invoke$0(ExecutableInvoker.java:105)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:104)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:98)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:212)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:208)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:137)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:71)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:135)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
    at java.util.ArrayList.forEach(ArrayList.java:1257)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
    at java.util.ArrayList.forEach(ArrayList.java:1257)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:248)
    at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$5(DefaultLauncher.java:211)
    at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:226)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:199)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:132)
    at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:71)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)

您可以注意到响应消息在上面的堆栈跟踪中被"Glo... (593 bytes)] 截断。如何记录完整的错误响应正文？

我知道我可以执行以下操作来打印错误响应正文，但是在许多类（以及其他应用程序）中添加的样板代码太多。

if(e instanceof HttpClientErrorException) {
    log.error("response body : " + ((HttpClientErrorException) e).getResponseBodyAsString());
}

1. 有什么方法可以记录Exception 对象将记录完整的错误响应消息正文而不是用... (593 bytes)] 截断？

2. java 中是否有一些默认大小限制，之后它会截断错误日志中的任何消息？如果是，如何更改？

更新：

在 jccampanero 回答之后，我向 Spring 团队提出了 this 问题，以使此日志消息大小限制可配置。他们完全取消了限制。此更改应该在 Spring 的某些未来版本中可用。

Answer 1

By default、RestTemplate 使用 DefaultErrorHandler 处理错误。

在这个类的实现中，不同的handleError 方法——例如this——依赖于getErrorMessage method：

/**
  * Return error message with details from the response body, possibly truncated:
  * <pre>
  * 404 Not Found: [{'id': 123, 'message': 'my very long... (500 bytes)]
  * </pre>
  */
private String getErrorMessage(
    int rawStatusCode, String statusText, @Nullable byte[] responseBody, @Nullable Charset charset) {


  String preface = rawStatusCode + " " + statusText + ": ";
  if (ObjectUtils.isEmpty(responseBody)) {
    return preface + "[no body]";
  }


  if (charset == null) {
    charset = StandardCharsets.UTF_8;
  }
  int maxChars = 200;


  if (responseBody.length < maxChars * 2) {
    return preface + "[" + new String(responseBody, charset) + "]";
  }


  try {
    Reader reader = new InputStreamReader(new ByteArrayInputStream(responseBody), charset);
    CharBuffer buffer = CharBuffer.allocate(maxChars);
    reader.read(buffer);
    reader.close();
    buffer.flip();
    return preface + "[" + buffer.toString() + "... (" + responseBody.length + " bytes)]";
  }
  catch (IOException ex) {
    // should never happen
    throw new IllegalStateException(ex);
  }
}

如您所见，这是实际截断消息的方法。

为了提供完整的消息，你可以自己提供ResponseErrorHandler实现。

例如重用DefaultErrorHandler中的代码实现：

import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;

import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.lang.Nullable;
import org.springframework.util.ObjectUtils;
import org.springframework.web.client.DefaultResponseErrorHandler;
import org.springframework.web.client.HttpClientErrorException;
import org.springframework.web.client.HttpServerErrorException;
import org.springframework.web.client.UnknownHttpStatusCodeException;

public class CustomRestTemplateResponseErrorHandler extends DefaultResponseErrorHandler {
  
  // This overloaded method version is only available since Spring 5.0
  // For previous versions of the library you can override
  // handleError(ClientHttpResponse response) instead
  @Override
  protected void handleError(ClientHttpResponse response, HttpStatus statusCode) throws IOException {
    String statusText = response.getStatusText();
    HttpHeaders headers = response.getHeaders();
    byte[] body = getResponseBody(response);
    Charset charset = getCharset(response);
    String message = getErrorMessage(statusCode.value(), statusText, body, charset);

    switch (statusCode.series()) {
      case CLIENT_ERROR:
        throw HttpClientErrorException.create(message, statusCode, statusText, headers, body, charset);
      case SERVER_ERROR:
        throw HttpServerErrorException.create(message, statusCode, statusText, headers, body, charset);
      default:
        throw new UnknownHttpStatusCodeException(message, statusCode.value(), statusText, headers, body, charset);
    }
  }

  /**
   * Return error message with details from the response body:
   * <pre>
   * 404 Not Found: [{'id': 123, 'message': 'actual mesage']
   * </pre>
   *
   * In contrast to <code>DefaultResponseErrorHandler</code>, the message will not be truncated.
   */
  private String getErrorMessage(
      int rawStatusCode, String statusText, @Nullable byte[] responseBody, @Nullable Charset charset) {

    String preface = rawStatusCode + " " + statusText + ": ";
    if (ObjectUtils.isEmpty(responseBody)) {
      return preface + "[no body]";
    }

    if (charset == null) {
      charset = StandardCharsets.UTF_8;
    }

    // return the message without truncation
    return preface + "[" + new String(responseBody, charset) + "]";
  }
}

然后，配置RestTemplate 以使用此自定义ResponseErrorHandler：

import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.springframework.web.client.HttpClientErrorException;
import org.springframework.web.client.RestTemplate;

@Slf4j
public class RestTemplateTest {

    @Test
    void shouldPrintErrorForRestTemplate() {
        RestTemplate restTemplate = new RestTemplate();
        ResponseErrorHandler errorHandler = new CustomRestTemplateResponseErrorHandler();
        restTemplate.setErrorHandler(errorHandler);

        try {
            restTemplate.getForEntity("http://hellosmilep.free.beeceptor.com/error/notfound", String.class);
        } catch (Exception e) {
            log.error("Error calling REST API", e);
        }
    }
}

请参阅this related SO question 或this article 了解更多示例。

Answer 2

如果你能捕捉到 HttpClientErrorException，而不是做一个，这样你就可以避免样板

@Test
void shouldPrintErrorForRestTemplate() {
    try {

        RestTemplate restTemplate = new RestTemplate();
        restTemplate.getForEntity("http://hellosmilep.free.beeceptor.com/error/notfound", String.class);

    } catch(HttpClientErrorException e) {
        log.error(e.getResponseBodyAsString(),e);
    }catch (Exception e) {
        log.error("Error calling REST API", e);
    }
}