Make a request with Apache HttpClient 2016-09-27 02:16
Sometimes we need request the resources programmatically. Apache HttpClient is one of the best way to make a request in your project. This blog will show you how to make "Get" and "Post" request for restful resource. The structure of this project is like following.
├─main
│ ├─java
│ │ └─com
│ │ └─henryxi
│ │ └─httpclient
│ │ │ RequestClient.java
│ │ │
│ │ └─service
│ │ ServerController.java
│ │ UserBean.java
│ │
│ └─resources
└─test
└─java
ServerController.java and UserBean.java
@RestController
@EnableAutoConfiguration
public class ServerController {
@RequestMapping(path = "/get", method = RequestMethod.GET)
public String get() {
UserBean userBean = new UserBean();
userBean.setAge(27);
userBean.setName("Henry");
return "This is Get response: " + userBean.toString();
}
@RequestMapping(path = "/post", method = RequestMethod.POST)
public String post(@RequestBody UserBean userBean) {
return "This is Post response:" + userBean.toString();
}
public static void main(String[] args) throws Exception {
SpringApplication.run(ServerController.class, args);
}
}
public class UserBean {
private String name;
private int age;
//getter and setter method
@Override
public String toString() {
return "UserBean{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}
This controller provides two interfaces for getting the resource. The one is for GET method and the other is for POST. You can use "PostMan" or something like that to test these RESTful interfaces. In this blog we will use HttpClient to request them.
RequestClient.java
public class RequestClient {
public static void main(String[] args) throws IOException {
CloseableHttpClient httpClient = HttpClients.createDefault();
HttpGet httpGet = new HttpGet("http://localhost:8080/get");
CloseableHttpResponse getResponse = httpClient.execute(httpGet);
System.out.println("get request status: " + getResponse.getStatusLine());
System.out.println("get request content: " + IOUtils.toString(getResponse.getEntity().getContent()));
HttpPost httpPost = new HttpPost("http://localhost:8080/post");
httpPost.setHeader("Content-Type", "application/json");
StringEntity postDate = new StringEntity("{ \"name\": \"henry\", \"age\": 27 }");
httpPost.setEntity(postDate);
CloseableHttpResponse postResponse = httpClient.execute(httpPost);
System.out.println("post request status: " + postResponse.getStatusLine());
System.out.println("post request content: " + IOUtils.toString(postResponse.getEntity().getContent()));
}
}
In RequestClient class we make two requests (GET and POST). We use IOUtils convert "inputStream" in response to String. The pom file should be like following.
<dependencies>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.3.3</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>1.3.3.RELEASE</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.4</version>
</dependency>
</dependencies>
How to test them?
Run the main method in ServerController and run the main method in RequestClient. You should get the log of RequestClient like following.
get request status: HTTP/1.1 200 OK
13:49:46.537 [main] DEBUG org.apache.http.wire - http-outgoing-0 << "This is Get response: UserBean{name='Henry', age=27}"
13:49:46.538 [main] DEBUG o.a.h.i.c.PoolingHttpClientConnectionManager - Connection [id: 0][route: {}->http://localhost:8080] can be kept alive indefinitely
13:49:46.538 [main] DEBUG o.a.h.i.c.PoolingHttpClientConnectionManager - Connection released: [id: 0][route: {}->http://localhost:8080][total kept alive: 1; route allocated: 1 of 2; total allocated: 1 of 20]
get request content: This is Get response: UserBean{name='Henry', age=27}
13:49:46.544 [main] DEBUG o.a.h.c.protocol.RequestAddCookies - CookieSpec selected: best-match
13:49:46.544 [main] DEBUG o.a.h.c.protocol.RequestAuthCache - Auth cache not set in the context
13:49:46.544 [main] DEBUG o.a.h.i.c.PoolingHttpClientConnectionManager - Connection request: [route: {}->http://localhost:8080][total kept alive: 1; route allocated: 1 of 2; total allocated: 1 of 20]
13:49:46.544 [main] DEBUG o.a.h.i.c.PoolingHttpClientConnectionManager - Connection leased: [id: 0][route: {}->http://localhost:8080][total kept alive: 0; route allocated: 1 of 2; total allocated: 1 of 20]
13:49:46.545 [main] DEBUG o.a.h.impl.execchain.MainClientExec - Stale connection check
13:49:46.546 [main] DEBUG org.apache.http.wire - http-outgoing-0 << "[read] I/O error: Read timed out"
13:49:46.546 [main] DEBUG o.a.h.impl.execchain.MainClientExec - Executing request POST /post HTTP/1.1
13:49:46.546 [main] DEBUG o.a.h.impl.execchain.MainClientExec - Target auth state: UNCHALLENGED
13:49:46.546 [main] DEBUG o.a.h.impl.execchain.MainClientExec - Proxy auth state: UNCHALLENGED
13:49:46.547 [main] DEBUG org.apache.http.headers - http-outgoing-0 >> POST /post HTTP/1.1
13:49:46.547 [main] DEBUG org.apache.http.headers - http-outgoing-0 >> Content-Type: application/json
13:49:46.549 [main] DEBUG org.apache.http.headers - http-outgoing-0 >> Content-Length: 34
13:49:46.550 [main] DEBUG org.apache.http.headers - http-outgoing-0 >> Host: localhost:8080
13:49:46.550 [main] DEBUG org.apache.http.headers - http-outgoing-0 >> Connection: Keep-Alive
13:49:46.550 [main] DEBUG org.apache.http.headers - http-outgoing-0 >> User-Agent: Apache-HttpClient/4.3.3 (java 1.5)
13:49:46.550 [main] DEBUG org.apache.http.headers - http-outgoing-0 >> Accept-Encoding: gzip,deflate
13:49:46.550 [main] DEBUG org.apache.http.wire - http-outgoing-0 >> "POST /post HTTP/1.1[\r][\n]"
13:49:46.550 [main] DEBUG org.apache.http.wire - http-outgoing-0 >> "Content-Type: application/json[\r][\n]"
13:49:46.550 [main] DEBUG org.apache.http.wire - http-outgoing-0 >> "Content-Length: 34[\r][\n]"
13:49:46.551 [main] DEBUG org.apache.http.wire - http-outgoing-0 >> "Host: localhost:8080[\r][\n]"
13:49:46.551 [main] DEBUG org.apache.http.wire - http-outgoing-0 >> "Connection: Keep-Alive[\r][\n]"
13:49:46.551 [main] DEBUG org.apache.http.wire - http-outgoing-0 >> "User-Agent: Apache-HttpClient/4.3.3 (java 1.5)[\r][\n]"
13:49:46.551 [main] DEBUG org.apache.http.wire - http-outgoing-0 >> "Accept-Encoding: gzip,deflate[\r][\n]"
13:49:46.551 [main] DEBUG org.apache.http.wire - http-outgoing-0 >> "[\r][\n]"
13:49:46.551 [main] DEBUG org.apache.http.wire - http-outgoing-0 >> "{ "name": "henry", "age": 27 }"
Disconnected from the target VM, address: '127.0.0.1:56880', transport: 'socket'
13:49:46.714 [main] DEBUG org.apache.http.wire - http-outgoing-0 << "HTTP/1.1 200 OK[\r][\n]"
13:49:46.714 [main] DEBUG org.apache.http.wire - http-outgoing-0 << "Server: Apache-Coyote/1.1[\r][\n]"
13:49:46.714 [main] DEBUG org.apache.http.wire - http-outgoing-0 << "Content-Type: text/plain;charset=UTF-8[\r][\n]"
13:49:46.714 [main] DEBUG org.apache.http.wire - http-outgoing-0 << "Content-Length: 52[\r][\n]"
13:49:46.714 [main] DEBUG org.apache.http.wire - http-outgoing-0 << "Date: Tue, 27 Sep 2016 05:49:46 GMT[\r][\n]"
13:49:46.714 [main] DEBUG org.apache.http.wire - http-outgoing-0 << "[\r][\n]"
13:49:46.714 [main] DEBUG org.apache.http.headers - http-outgoing-0 << HTTP/1.1 200 OK
13:49:46.714 [main] DEBUG org.apache.http.headers - http-outgoing-0 << Server: Apache-Coyote/1.1
13:49:46.714 [main] DEBUG org.apache.http.headers - http-outgoing-0 << Content-Type: text/plain;charset=UTF-8
13:49:46.714 [main] DEBUG org.apache.http.headers - http-outgoing-0 << Content-Length: 52
13:49:46.715 [main] DEBUG org.apache.http.headers - http-outgoing-0 << Date: Tue, 27 Sep 2016 05:49:46 GMT
13:49:46.715 [main] DEBUG o.a.h.impl.execchain.MainClientExec - Connection can be kept alive indefinitely
post request status: HTTP/1.1 200 OK
13:49:46.715 [main] DEBUG org.apache.http.wire - http-outgoing-0 << "This is Post response:UserBean{name='henry', age=27}"
13:49:46.715 [main] DEBUG o.a.h.i.c.PoolingHttpClientConnectionManager - Connection [id: 0][route: {}->http://localhost:8080] can be kept alive indefinitely
13:49:46.715 [main] DEBUG o.a.h.i.c.PoolingHttpClientConnectionManager - Connection released: [id: 0][route: {}->http://localhost:8080][total kept alive: 1; route allocated: 1 of 2; total allocated: 1 of 20]
post request content: This is Post response:UserBean{name='henry', age=27}