纯 java 实现 Http 资源读取工具，支持发送和接收数据，不依赖任何第三方 jar 包

/*
 *    Copyright 2012-2013 The Haohui Network Corporation
 */
package com.haohui.common.utils;

/**
 * @file HttpUtil.java
 * 
 * @brief 
 * HttpUtil is a single class containing methods to conveniently perform HTTP 
 * requests. HttpUtil only uses regular java io and net functionality and does 
 * not depend on external libraries. 
 * The class contains methods to perform a get, post, put, and delete request,
 * and supports posting forms. Optionally, one can provide headers.
 *
 * Example usage:
 * 
 *     // get
 *     String res = HttpUtil.get("http://www.zuidaima.com");
 * 
 *     // post
 *     String res = HttpUtil.post("http://www.zuidaima.com/share/1550463379950592.htm", "This is the data");
 *
 *     // post form
 *     Map<String, String> params = new HashMap<String, String>();
 *     params.put("firstname", "Joe");
 *     params.put("lastname", "Smith");
 *     params.put("age", "28");
 *     String res = HttpUtil.postForm("http://site.com/newuser", params);
 *
 *     // append query parameters to url
 *     String url = "http://mydatabase.com/users";
 *     Map<String, String> params = new HashMap<String, String>();
 *     params.put("orderby", "name");
 *     params.put("limit", "10");
 *     String fullUrl = HttpUtil.appendQueryParams(url, params);
 *     // fullUrl = "http://mydatabase.com/user?orderby=name&limit=10"
 *
 * @license
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy 
 * of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 *
 * Copyright (c) 2012 Almende B.V.
 *
 * @author 	Jos de Jong, <jos@almende.org> www.zuidaima.com
 * @date	  2012-05-14
 */

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Map;

/**
 * https://raw.github.com/wjosdejong/httputil/master/src/com/almende/util/HttpUtil.java
 * 
 * @project baidamei
 * @author cevencheng <cevencheng@gmail.com>
 * @create 2012-11-17 下午2:35:38
 */
public class HttpUtil {
	/**
	 * Send a get request
	 * @param url
	 * @return response
	 * @throws IOException 
	 */
	static public String get(String url) throws IOException {
		return get(url, null);
	}

	/**
	 * Send a get request
	 * @param url         Url as string
	 * @param headers     Optional map with headers
	 * @return response   Response as string
	 * @throws IOException 
	 */
	static public String get(String url,
			Map<String, String> headers) throws IOException {
		return fetch("GET", url, null, headers);
	}

	/**
	 * Send a post request
	 * @param url         Url as string
	 * @param body        Request body as string
	 * @param headers     Optional map with headers
	 * @return response   Response as string
	 * @throws IOException 
	 */
	static public String post(String url, String body,
			Map<String, String> headers) throws IOException {
		return fetch("POST", url, body, headers);
	}

	/**
	 * Send a post request
	 * @param url         Url as string
	 * @param body        Request body as string
	 * @return response   Response as string
	 * @throws IOException 
	 */
	static public String post(String url, String body) throws IOException {
		return post(url, body, null);
	}

	/**
	 * Post a form with parameters
	 * @param url         Url as string
	 * @param params      map with parameters/values
	 * @return response   Response as string
	 * @throws IOException 
	 */
	static public String postForm(String url, Map<String, String> params) 
			throws IOException {
		return postForm(url, params, null);
	}

	/**
	 * Post a form with parameters
	 * @param url         Url as string
	 * @param params      Map with parameters/values
	 * @param headers     Optional map with headers
	 * @return response   Response as string
	 * @throws IOException 
	 */
	static public String postForm(String url, Map<String, String> params,
			Map<String, String> headers) throws IOException {
		// set content type
		if (headers == null) {
			headers = new HashMap<String, String>();
		}
		headers.put("Content-Type", "application/x-www-form-urlencoded");

		// parse parameters
		String body = "";
		if (params != null) {
			boolean first = true;
			for (String param : params.keySet()) {
				if (first) {
					first = false;
				}
				else {
					body += "&";
				}
				String value = http://www.mamicode.com/params.get(param);>
 
纯 java 实现 Http 资源读取工具，支持发送和接收数据，不依赖任何第三方 jar 包