spring - Rest Template 自定义异常处理

Question

我正在使用来自外部 API 的一些 REST 端点，并且为此目的使用了 Rest Template 接口(interface)。当我从这些调用中收到某些 HTTP 状态代码时，我希望能够引发自定义应用程序异常。为了实现它，我正在实现 ResponseErrorHandler 接口(interface)，如下所示:

public class MyCustomResponseErrorHandler implements ResponseErrorHandler {

    private ResponseErrorHandler myErrorHandler = new DefaultResponseErrorHandler();

    public boolean hasError(ClientHttpResponse response) throws IOException {
        return myErrorHandler.hasError(response);
    }

    public void handleError(ClientHttpResponse response) throws IOException {
        String body = IOUtils.toString(response.getBody());
        MyCustomException exception = new MyCustomException(response.getStatusCode(), body, body);
        throw exception;
    }

}

public class MyCustomException extends IOException {

    private HttpStatus statusCode;

    private String body;

    public MyCustomException(String msg) {
        super(msg);
        // TODO Auto-generated constructor stub
    }

    public MyCustomException(HttpStatus statusCode, String body, String msg) {
        super(msg);
        this.statusCode = statusCode;
        this.body = body;
    }

    public HttpStatus getStatusCode() {
        return statusCode;
    }

    public void setStatusCode(HttpStatus statusCode) {
        this.statusCode = statusCode;
    }

    public String getBody() {
        return body;
    }

    public void setBody(String body) {
        this.body = body;
    }

}

最后，这是客户端代码(无关代码省略):

public LoginResponse doLogin(String email, String password) {
    HttpEntity<?> requestEntity = new HttpEntity<Object>(crateBasicAuthHeaders(email,password));
    try{
        ResponseEntity<LoginResponse> responseEntity = restTemplate.exchange(myBaseURL + "/user/account/" + email, HttpMethod.GET, requestEntity, LoginResponse.class);
        return responseEntity.getBody();
    } catch (Exception e) {
        //Custom error handler in action, here we're supposed to receive a MyCustomException
        if (e instanceof MyCustomException){
            MyCustomException exception = (MyCustomException) e;
            logger.info("An error occurred while calling api/user/account API endpoint: " + e.getMessage());
        } else {
             logger.info("An error occurred while trying to parse Login Response JSON object");
        }
    }
    return null;
}

我的应用上下文:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:spring="http://camel.apache.org/schema/spring"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">

    <!-- Rest template (used in bridge communication) -->
    <bean id="restTemplate" class="org.springframework.web.client.RestTemplate">
        <property name="errorHandler" ref="myCustomResponseErrorHandler"></property>
    </bean>

    <!-- Bridge service -->
    <bean id="myBridgeService" class="a.b.c.d.service.impl.MyBridgeServiceImpl"/>

    <!-- Bridge error handler -->
    <bean id="myCustomResponseErrorHandler" class="a.b.c.d.service.handlers.MyCustomResponseErrorHandler"/>

</beans>

我怀疑我没有正确理解这种自定义错误处理的行为。每个单独的 rest 模板方法都可能抛出一个 RestClientException，它遵循异常层次结构，是 RuntimeException 的子类，而不是在自定义响应错误处理程序中引发的 IOException，即:I can't catch my custom exception in the rest template method来电。

关于如何捕获这些异常的任何线索？ Spring RestTemplate invoking webservice with errors and analyze status code是高度相关的，但从我的角度来看，经历了同样的问题，尽管它是作为解决方案提出的。

[1]:

Answer 1

你已经定制了Exception延伸自 IOException

public class MyCustomException extends IOException {

ResponseErrorHandler#handleError()方法从 RestTemplate#handleResponseError(..) 调用由 RestTemplate#doExecute(..) 调用.此根调用包含在 try-catch 中捕获 IOException 的 block 并重新抛出它包裹在 ResourceAccessException 中，这是一个 RestClientException .

一种可能性是捕获 RestClientException并得到它的 cause .

另一种可能性是使您的自定义 Exception是 RuntimeException 的子类型.