Java学习——Jetty编程使用HttpClient

kaywang

Jetty不仅可以拥有方便的服务器组件，也能很方便地发起Http请求。
Jetty的HttpClient组件可以用来向web服务器发起HTTP请求，解析响应内容，它有下面一些特性，比起JRE自带的要强大很多
1，默认是异步，也可以指定为同步
2，默认是非阻塞连接，也可以指定阻塞connectors
3，支持SSL协议
4，支持HTTP代理
5，支持HTTP认证机制
6，可以详细配置超时，连接数，线程池等设置
 
 
HttpClient API提供回调接口异步地处理服务器端返回，一个请求响应单元被成为exchange，HttpClient API里面有两个主要的类
org.eclipse.jetty.client.HttpClient 管理线程池，代理设置，Http认证的配置，connector类型设置，ssl以及超时等其它于特定一个交互无关的所有配置。
org.eclipse.jetty.client.HttpExchange 需要编程继承的父类，控制特定一次Http请求的所有相关内容（请求头，请求方法，响应内容等等）

package test.jetty;
import java.io.IOException;
import org.eclipse.jetty.client.Address;
import org.eclipse.jetty.client.HttpClient;
import org.eclipse.jetty.client.HttpExchange;
import org.eclipse.jetty.io.Buffer;
import org.eclipse.jetty.util.thread.QueuedThreadPool;
public class TestClient{
public static void main(String[] args) throws Exception {
HttpClient client = new HttpClient();
client.setConnectorType(HttpClient.CONNECTOR_SELECT_CHANNEL);
client.setThreadPool(new QueuedThreadPool(50));
client.setMaxConnectionsPerAddress(10);
client.setTimeout(5000);
//启动之前先配置好
client.start();
HttpExchange exchange = new HttpExchange(){
@Override
public void onConnectionFailed(Throwable arg0) {
// TODO Auto-generated method stub
System.err.println("failed to connect web server");
}
@Override
public void onException(Throwable arg0) {
// TODO Auto-generated method stub
System.err.println("unknown error");
}
@Override
public void onExpire() {
// TODO Auto-generated method stub
System.err.println("timeout");
}
@Override
public void onRequestCommitted() throws IOException {
// TODO Auto-generated method stub
System.out.println("request commited");
}
@Override
public void onRequestComplete() throws IOException {
// TODO Auto-generated method stub
System.out.println("request complete");
}
@Override
public void onResponseComplete() throws IOException {
// TODO Auto-generated method stub
System.out.println("response complete");
}
@Override
public void onResponseContent(Buffer arg0) throws IOException {
// TODO Auto-generated method stub
System.out.println("response content");
System.out.println(arg0.toString());
}
@Override
public void onResponseHeader(Buffer arg0, Buffer arg1) throws IOException {
// TODO Auto-generated method stub
System.out.println("response header");
System.out.println(arg0.toString() + " " + arg1.toString());
}
@Override
public void onResponseStatus(Buffer arg0, int arg1, Buffer arg2)
throws IOException {
// TODO Auto-generated method stub
System.out.println("response status");
System.out.println(arg0.toString() + " " + arg1 + " " + arg2.toString());
}
@Override
public void onRetry() {
// TODO Auto-generated method stub
System.out.println("retry request");
}
@Override
public void onResponseHeaderComplete() throws IOException {
// TODO Auto-generated method stub
System.out.println("response header complete");
}
};
exchange.setMethod("GET");
exchange.setAddress(new Address("www.baidu.com",80));
exchange.setRequestURI("/");
//client.send会立即返回，exchange会被分发给线程池去处理，
client.send(exchange);
System.out.println("send");
}
}
　　运行结果

send
request commited
request complete
response status
HTTP/1.1 200 OK
response header
Date Sun, 23 Dec 2012 10:14:30 GMT
response header
Server BWS/1.0
response header
Content-Length 9777
response header
Content-Type text/html;charset=gbk
response header
Cache-Control private
response header
Expires Sun, 23 Dec 2012 10:14:30 GMT
response header
Set-Cookie BAIDUID=9E28256B347526A1BE2FA301AE032CE7:FG=1; expires=Sun, 23-Dec-42 10:14:30 GMT; path=/; domain=.baidu.com
response header
P3P CP=" OTI DSP COR IVA OUR IND COM "
response header
Connection Keep-Alive
response header complete
response content
…content…
response complete
　　上面的示例代码演示了异步请求，下面的代码演示如何做同步请求。
 

package test.jetty;
import org.eclipse.jetty.client.Address;
import org.eclipse.jetty.client.ContentExchange;
import org.eclipse.jetty.client.HttpClient;
import org.eclipse.jetty.util.thread.QueuedThreadPool;
public class TestClient{
public static void main(String[] args) throws Exception {
HttpClient client = new HttpClient();
client.setConnectorType(HttpClient.CONNECTOR_SELECT_CHANNEL);
client.setThreadPool(new QueuedThreadPool(50));
client.setMaxConnectionsPerAddress(10);
client.setTimeout(5000);
//启动之前先配置好
client.start();
ContentExchange exchange = new ContentExchange();
exchange.setMethod("GET");
exchange.setAddress(new Address("www.baidu.com",80));
exchange.setRequestURI("/");
//client.send会立即返回，exchange会被分发给线程池去处理，
client.send(exchange);
System.out.println("send");
//阻塞等待
exchange.waitForDone();
System.out.println(exchange.getResponseStatus());
//System.out.println(exchange.getResponseContentBytes());
System.out.println(exchange.getResponseContent());
}
}
　　还不知道在同步的情况下ContentExchange的哪个方法可以获取到响应头信息。。。