HttpURLConnection的详细用法

[xiejiangjun]

有谁能为我介绍一下HttpURLConnection，最好给点示例，万分感谢！

[悠悠的爸爸]

看文档阿。

[ericsome]

和URLConnection是一样的

new URLConnection(new URL())就成

[wys1978]

a class from an open source package , it use HttpURLConnection to make a HttpClient , hope help:

Part I:
/*
* $Id: HttpClient.java,v 1.4 2002/02/08 09:06:25 jonesde Exp $
*
* Copyright (c) 2001 The Open For Business Project - www.ofbiz.org
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT
* OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
* THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

package org.ofbiz.core.util;

import java.io.DataOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.util.HashMap;
import java.util.Set;
import java.util.Iterator;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;

/**
* Send HTTP GET/POST requests.
*
* @author <a href="mailto:[e-mail]">Andy Zeneski</a>
* @version 1.0
* @created June 29, 2001
*/
public class HttpClient {

private String url = null;
private boolean lineFeed = true;
private HashMap parameters = null;
private HashMap headers = null;
private URL requestUrl;
private URLConnection con;

/** Creates an empty HttpClient object. */
public HttpClient() {
}

/** Creates a new HttpClient object. */
public HttpClient(URL url) {
this.url = url.toExternalForm();
}

/** Creates a new HttpClient object. */
public HttpClient(String url) {
this.url = url;
}

/** Creates a new HttpClient object. */
public HttpClient(String url, HashMap parameters) {
this.url = url;
this.parameters = parameters;
}

/** Creates a new HttpClient object. */
public HttpClient(URL url, HashMap parameters) {
this.url = url.toExternalForm();
this.parameters = parameters;
}

/** Creates a new HttpClient object. */
public HttpClient(String url, HashMap parameters, HashMap headers) {
this.url = url;
this.parameters = parameters;
this.headers = headers;
}

/** Creates a new HttpClient object. */
public HttpClient(URL url, HashMap parameters, HashMap headers) {
this.url = url.toExternalForm();
this.parameters = parameters;
this.headers = headers;
}

/** Turns on or off line feeds in the request. (default is on) */
public void setLineFeed(boolean lineFeed) {
this.lineFeed = lineFeed;
}

/** Set the URL for this request. */
public void setUrl(URL url) {
this.url = url.toExternalForm();
}

/** Set the URL for this request. */
public void setUrl(String url) {
this.url = url;
}

/** Set the parameters for this request. */
public void setParameters(HashMap parameters) {
this.parameters = parameters;
}

/** Set an individual parameter for this request. */
public void setParameter(String name, String value) {
if (parameters == null)
parameters = new HashMap();
parameters.put(name, value);
}

/** Set the headers for this request. */
public void setHeaders(HashMap headers) {
this.headers = headers;
}

/** Set an individual header for this request. */
public void setHeader(String name, String value) {
if (headers == null)
headers = new HashMap();
headers.put(name, value);
}

/** Return a HashMap of headers. */
public HashMap getHeaders() {
return headers;
}

/** Return a HashMap of parameters. */
public HashMap getParameters() {
return parameters;
}

/** Return a string representing the requested URL. */
public String getUrl() {
return url;
}

/** Invoke HTTP request GET. */
public String get() throws HttpClientException {
return sendHttpRequest("get");
}

/** Invoke HTTP request GET. */
public InputStream getStream() throws HttpClientException {
return sendHttpRequestStream("get");
}

/** Invoke HTTP request POST. */
public String post() throws HttpClientException {
return sendHttpRequest("post");
}

/** Invoke HTTP request POST. */
public InputStream postStream() throws HttpClientException {
return sendHttpRequestStream("post");
}

/** Returns the value of the specified named response header field. */
public String getResponseHeader(String header) {
return con.getHeaderField(header);
}

/** Returns the key for the nth response header field. */
public String getResponseHeaderFieldKey(int n) {
return con.getHeaderFieldKey(n);
}

[wys1978]

Part II:


/** Returns the value for the nth response header field. It returns null of there are fewer then n fields. */
public String getResponseHeaderField(int n) {
return con.getHeaderField(n);
}

/** Returns the content of the response. */
public Object getResponseContent() throws java.io.IOException {
return con.getContent();
}

/** Returns the content-type of the response. */
public String getResponseContentType() {
return con.getContentType();
}

/** Returns the content length of the response */
public int getResponseContentLength() {
return con.getContentLength();
}

/** Returns the content encoding of the response. */
public String getResponseContentEncoding() {
return con.getContentEncoding();
}

private String sendHttpRequest(String method) throws HttpClientException {
InputStream in = sendHttpRequestStream(method);
if (in == null) return null;

StringBuffer buf = new StringBuffer();
try {
BufferedReader post = new BufferedReader(new InputStreamReader(in));
String line = new String();
while ((line = post.readLine()) != null) {
buf.append(line);
if (lineFeed)
buf.append("\n");
}
} catch (Exception e) {
throw new HttpClientException("Error processing input stream", e);
}
return buf.toString();
}

private InputStream sendHttpRequestStream(String method) throws HttpClientException {
String arguments = null;
InputStream in = null;

if (url == null)
throw new HttpClientException("Cannot process a null URL.");

if (parameters != null && parameters.size() > 0)
arguments = encodeArgs(parameters);

// Append the arguments to the query string if GET.
if (method.equalsIgnoreCase("get") && arguments != null)
url = url + "?" + arguments;

// Create the URL and open the connection.
try {
requestUrl = new URL(url);
con = requestUrl.openConnection();
con.setDoOutput(true);
con.setUseCaches(false);

if (method.equalsIgnoreCase("post")) {
con.setRequestProperty("Content-type", "application/x-www-form-urlencoded");
con.setDoInput(true);
}

if (headers != null && headers.size() > 0) {
Set headerSet = headers.keySet();
Iterator i = headerSet.iterator();
while (i.hasNext()) {
String headerName = (String) i.next();
String headerValue = (String) headers.get(headerName);
con.setRequestProperty(headerName, headerValue);
}
}

if (method.equalsIgnoreCase("post")) {
DataOutputStream out = new DataOutputStream(con.getOutputStream());
out.writeBytes(arguments);
out.flush();
out.close();
}

in = con.getInputStream();
} catch (Exception e) {
throw new HttpClientException("Error processing request", e);
}

return in;
}

private String encodeArgs(HashMap args) {
StringBuffer buf = new StringBuffer();
Set names = args.keySet();
Iterator i = names.iterator();
while (i.hasNext()) {
String name = (String) i.next();
String value = (String) args.get(name);
buf.append(URLEncoder.encode(name));
buf.append("=");
buf.append(URLEncoder.encode(value));
if (i.hasNext())
buf.append("&");
}
return buf.toString();
}
}