如何开启 Spring RestTemplate 的日志信息

Spring提供了非常方便使用的RestTemplate，用于访问http/https资源。但在开发调试过程中，我们希望能够看到相关的日志信息。

开启日志

修改application.properties文件，加入以下配置：

logging.level.org.springframework.web.client.RestTemplate=DEBUG

可以看到类似以下的日志信息：

o.s.w.c.RestTemplate - HTTP POST http://localhost:8082/spring-rest/persons
o.s.w.c.RestTemplate - Accept=[text/plain, application/json, application/*+json, */*]
o.s.w.c.RestTemplate - Writing [my request body] with org.springframework.http.converter.StringHttpMessageConverter
o.s.w.c.RestTemplate - Response 200 OK

但非常遗憾的是，没有response body的日志信息，而这部分信息通常非常重要。

使用 Apache HttpClient

可以让Spring的RestTemplate使用Apache HttpClient处理http/https请求，这样就可以看到完整的日志。

加入依赖：

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.12</version>
</dependency>

设置RestTemplate的RequestFactory为HttpComponentsClientHttpRequestFactory：

RestTemplate restTemplate = new RestTemplate();
restTemplate.setRequestFactory(new HttpComponentsClientHttpRequestFactory());

修改application.properties文件，加入以下配置：

logging.level.org.apache.http=DEBUG
logging.level.httpclient.wire=DEBUG

这样就可以看到http/https请求的完整日志了：

o.a.http.headers - http-outgoing-0 >> POST /spring-rest/persons HTTP/1.1
o.a.http.headers - http-outgoing-0 >> Accept: text/plain, application/json, application/*+json, */*
// ... more request headers
o.a.http.headers - http-outgoing-0 >> User-Agent: Apache-HttpClient/4.5.9 (Java/1.8.0_171)
o.a.http.headers - http-outgoing-0 >> Accept-Encoding: gzip,deflate
org.apache.http.wire - http-outgoing-0 >> "POST /spring-rest/persons HTTP/1.1[\r][\n]"
org.apache.http.wire - http-outgoing-0 >> "Accept: text/plain, application/json, application/*+json, */*[\r][\n]"
org.apache.http.wire - http-outgoing-0 >> "Content-Type: text/plain;charset=ISO-8859-1[\r][\n]"
// ... more request headers
org.apache.http.wire - http-outgoing-0 >> "[\r][\n]"
org.apache.http.wire - http-outgoing-0 >> "my request body"
org.apache.http.wire - http-outgoing-0 << "HTTP/1.1 200 [\r][\n]"
org.apache.http.wire - http-outgoing-0 << "Content-Type: application/json[\r][\n]"
// ... more response headers
org.apache.http.wire - http-outgoing-0 << "Connection: keep-alive[\r][\n]"
org.apache.http.wire - http-outgoing-0 << "[\r][\n]"
org.apache.http.wire - http-outgoing-0 << "21[\r][\n]"
org.apache.http.wire - http-outgoing-0 << "["Lucie","Jackie","Danesh","Tao"][\r][\n]"

参考资料

• Spring RestTemplate Request/Response Logging