【学习】从HttpClient3迁移到HttpClient4

网上很多HttpClient的学习源码都是3版本的，不过，既然现在HttpClient已经升级成Apache的顶级项目，自然想使用新版本。但是4版本完全是重新编写，而不能向下兼容。所以在学习调试源码时，利用的4的库，就不能直接运行3.1下的源码。

结合网上资源或自己实践，把3迁移4的一些资料收集整理于此，于己于人都会有帮助。

1. jar包的变更，可以在此下载最新的jar包：http://hc.apache.org/downloads.cgi
2. 把org.apache.commons.httpclient.*修改到import org.apache.http.*。具体变更哪些，就要看利用了HttpClient的哪些功能
   比如：
   

   import org.apache.commons.httpclient.HttpClient;
   import org.apache.commons.httpclient.HttpStatus;
   import org.apache.commons.httpclient.HttpException;
   import org.apache.commons.httpclient.methods.GetMethod;
   import org.apache.commons.httpclient.ConnectTimeoutException;

   To
   

   import org.apache.http.client.HttpClient;
   import org.apache.http.HttpStatus;
   import org.apache.http.HttpException;
   import org.apache.http.client.methods.HttpGet;
   import org.apache.http.conn.ConnectTimeoutException;
   import org.apache.http.HttpResponse;
   import org.apache.http.impl.client.DefaultHttpClient;

     
3. 使用的各个HttpClient的功能的代码修改。这部分的整理，在使用过程中慢慢补全。本次先介绍Get方法的修改。

GET方法：

HttpClient3.1的代码：

HttpClient client = new HttpClient();

GetMethod method = new GetMethod(url);
int statusCode = client.executeMethod(method);
if (statusCode == HttpStatus.SC_OK) {
    InputStream is = method.getResponseBodyAsStream();
    // do something with the input stream
}
method.releaseConnection();

To

HttpClient4.0的代码：

HttpClient client = new DefaultHttpClient();

HttpGet method = new HttpGet(url);
HttpResponse httpResponse = client.execute(method);
int statusCode = httpResponse.getStatusLine().getStatusCode();
if (statusCode == HttpStatus.SC_OK) {
    InputStream is = httpResponse.getEntity().getContent();
    // do something with the input stream
}

 

哪位有更完整的资料，求分享！

参考：

 http://blog.teamextension.com/migrating-from-httpclient-3-1-to-4-0-34