一尘不染

Rest Template自定义异常处理

spring-mvc

我正在使用来自外部API的一些REST端点,并且为此使用了Rest
Template接口。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,我实现了ResponseErrorHandler接口,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(省略了无关的代码):

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;
}

我的应用环境:

<?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此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RestClientException,该异常遵循异常层次结构,它是RuntimeException的子类,而不是IOException,它是在自定义响应错误处理程序中抛出的,即:我无法在rest模板方法中捕获我的自定义异常电话。

关于如何捕获这些异常的任何线索?Spring
RestTemplate调用带有错误的Web服务并分析状态代码是高度相关的,但是从我的角度来看,尽管它是作为解决方案提出的,但我仍然遇到相同的问题。

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2020-06-01

共1个答案

一尘不染

您已将自定义Exception扩展自IOException

public class MyCustomException extends IOException {

ResponseErrorHandler#handleError()方法是从调用RestTemplate#handleResponseError(..)其通过调用RestTemplate#doExecute(..)。此根调用被包装在一个try- catch块中,该块被捕获IOException并重新包装在a中ResourceAccessException,即a
RestClientException

一种可能性是抓住RestClientException并获得成功cause

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

2020-06-01