How do I log response in Spring RestTemplate?

Question

I am using RestTemplate to make calls to a web service.

String userId = restTemplate.getForObject(createUserUrl, String.class);

If this fails to return a user ID I just get returned null but I don't know why. How do I output the actual XML response to a log?

Answer 1

Configure your logging as follows:

log4j.logger.org.springframework.web.client=DEBUG

Then use a curl command to see the output, eg

curl  -H 'Accept: application/xml' -H 'Content-Type: application/xml' http://localhost:8080/ser/data

By default, restTemplate uses HttpURlConnection (via SimpleClientHttpRequest), so you might need to switch to jakarta httpclient to see the log statement. Otherwise the above log configuration will out show you the response

    <bean id="httpClientFactory" class="org.springframework.http.client.CommonsClientHttpRequestFactory">
        <constructor-arg><bean  class="org.apache.commons.httpclient.HttpClient"/></constructor-arg>
    </bean>
    <bean id="restTemplate" class="org.springframework.web.client.RestTemplate">
        <constructor-arg ref="httpClientFactory"/>
        <property name="messageConverters">
...

Answer 2

Depending on which method of making the HTTP connection you are using, you could look at turning up the logging within the actual HTTP connection classes.

For example, if you are using commons HttpClient, you can set

log4j.logger.httpclient.wire=DEBUG

The commons-httpclient project has an entire page in the documentation on their logging practices.

Answer 3

You can use spring-rest-template-logger to log RestTemplate HTTP traffic.

Add a dependency to your Maven project:

<dependency>
    <groupId>org.hobsoft.spring</groupId>
    <artifactId>spring-rest-template-logger</artifactId>
    <version>2.0.0</version>
</dependency>

Then customize your RestTemplate as follows:

RestTemplate restTemplate = new RestTemplateBuilder()
    .customizers(new LoggingCustomizer())
    .build()

Now all RestTemplate HTTP traffic will be logged to org.hobsoft.spring.resttemplatelogger.LoggingCustomizer at debug level.

DISCLAIMER: I wrote this library.