1、响应处理器（Response handling）
如何使用response处理器来处理HTTP响应。这是执行请求和处理响应的推荐方式。它使得使用者更关注HTTP响应的处理，而将系统资源的处理交给HttpClient来处理。使用HTTP响应处理器将会保证在任何时候都要保证相关联的连接都会自动被连接管理器回收。
CloseableHttpClient httpclient = HttpClients.createDefault();
try {
HttpGet httpget = new HttpGet("http://localhost/");
System.out.println("Executing request " + httpget.getRequestLine());
// Create a custom response handler
ResponseHandler<String> responseHandler = new ResponseHandler<String>() {
public String handleResponse(
final HttpResponse response) throws ClientProtocolException, IOException {
int status = response.getStatusLine().getStatusCode();
if (status > 200 && status < 300) {
HttpEntity entity = response.getEntity();
return entity != null ? EntityUtils.toString(entity) : null;
} else {
throw new ClientProtocolException("Unexpected response status: " + status);
}
}
};
String responseBody = httpclient.execute(httpget, responseHandler);
System.out.println("----------------------------------------");
System.out.println(responseBody);
} finally {
httpclient.close();
}
2、手动释放链接
该例子示范了在手动操作HTTP响应时，如何确保将关联的链接回收至连接管理器中。
CloseableHttpClient httpclient = HttpClients.createDefault();
try {
HttpGet httpget = new HttpGet("http://localhost/");
System.out.println("Executing request " + httpget.getRequestLine());
CloseableHttpResponse response = httpclient.execute(httpget);
try {
System.out.println("----------------------------------------");
System.out.println(response.getStatusLine());
// Get hold of the response entity
HttpEntity entity = response.getEntity();
// If the response does not enclose an entity, there is no need
// to bother about connection release
if (entity != null) {
InputStream instream = entity.getContent();
try {
instream.read();
// do something useful with the response
} catch (IOException ex) {
// In case of an IOException the connection will be released
// back to the connection manager automatically
throw ex;
} finally {
// Closing the input stream will trigger connection release
instream.close();
}
}
} finally {
response.close();
}
} finally {
httpclient.close();
}
