HttpClientUtil-用于后台发起请求

项目中经常需要通过apache的http client模拟发送请求，于是动手写了HttpClientUtil这个工具类。该工具类主要出于下面几个方面考虑作设计：

1、具备发送http post请求的功能；

2、请求参数编码和读取内容编码的设置，解决乱码问题；

3、请求超时和连接关闭。

通过单例模式，提供HttpClientUtil的实例，提供的API有：

//获取单例对象，并设置默认的页面编码public static HttpClientUtil getInstance(String urlCharset);//设置编码public void setUrlCharset(String urlCharset);//获取字符串型返回结果，通过发起http post请求public String getResponseBodyAsString(String targetUrl,Map params)throws Exception;//获取字符数组型返回结果，通过发起http post请求public byte[] getResponseBodyAsByteArray(String targetUrl,Map params)throws Exception;//将response的返回流写到outputStream中，通过发起http post请求public void getResponseBodyAsStream(String targetUrl,Map params,OutputStream outputStream)throws Exception;

完整的代码如下：

/* * 创建日期 2014-3-13 * * TODO 要更改此生成的文件的模板，请转至 * 窗口 － 首选项 － Java － 代码样式 － 代码模板 */package com.excellence.explatform.client.util;import java.io.File;import java.io.FileOutputStream;import java.io.InputStream;import java.io.OutputStream;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Set;import org.apache.commons.httpclient.HttpClient;import org.apache.commons.httpclient.HttpStatus;import org.apache.commons.httpclient.NameValuePair;import org.apache.commons.httpclient.SimpleHttpConnectionManager;import org.apache.commons.httpclient.methods.PostMethod;import org.apache.commons.httpclient.params.HttpClientParams;import org.apache.commons.httpclient.params.HttpMethodParams;import org.apache.commons.lang.StringUtils;/** * @author administrator * * Http Client工具类 * 发起http client 请求 *  * 窗口 － 首选项 － Java － 代码样式 － 代码模板 */public final class HttpClientUtil {private static final String TYPE_STRING = "string";private static final String TYPE_BYTEARRAY = "byte[]";private static final String TYPE_STREAM = "stream";private static HttpClientUtil instance;private HttpClientUtil(){}/** * 使用默认的页面请求编码：utf-8 * @return */public static HttpClientUtil getInstance(){return getInstance("UTF-8");} public static HttpClientUtil getInstance(String urlCharset){if(instance == null){instance = new HttpClientUtil();}//设置默认的url编码instance.setUrlCharset(urlCharset);return instance;}/** * 请求编码，默认使用utf-8 */private String urlCharset = "UTF-8";/** * @param urlCharset 要设置的 urlCharset。 */public void setUrlCharset(String urlCharset) {this.urlCharset = urlCharset;}/** * 获取字符串型返回结果，通过发起http post请求 * @param targetUrl * @param params * @return * @throws Exception */public String getResponseBodyAsString(String targetUrl,Map params)throws Exception{return (String)setPostRequest(targetUrl,params,TYPE_STRING,null);}/** * 获取字符数组型返回结果，通过发起http post请求 * @param targetUrl * @param params * @return * @throws Exception */public byte[] getResponseBodyAsByteArray(String targetUrl,Map params)throws Exception{return (byte[])setPostRequest(targetUrl,params,TYPE_BYTEARRAY,null);}/** * 将response的返回流写到outputStream中，通过发起http post请求 * @param targetUrl请求地址 * @param params请求参数<paramName,paramValue> * @param outputStream输出流 * @throws Exception */public void getResponseBodyAsStream(String targetUrl,Map params,OutputStream outputStream)throws Exception{if(outputStream == null){throw new IllegalArgumentException("调用HttpClientUtil.setPostRequest方法，targetUrl不能为空!");}//response 的返回结果写到输出流setPostRequest(targetUrl,params,TYPE_STREAM,outputStream);}/** * 利用http client模拟发送http post请求 * @param targetUrl请求地址 * @param params请求参数<paramName,paramValue> * @returnObject返回的类型可能是：String 或者 byte[] 或者 outputStream * @throws Exception */private Object setPostRequest(String targetUrl,Map params,String responseType,OutputStream outputStream)throws Exception{if(StringUtils.isBlank(targetUrl)){throw new IllegalArgumentException("调用HttpClientUtil.setPostRequest方法，targetUrl不能为空!");}Object responseResult = null;HttpClient client = null;PostMethod post = null;NameValuePair[] nameValuePairArr = null;SimpleHttpConnectionManager connectionManager = null;try{connectionManager =  new SimpleHttpConnectionManager(true);//连接超时,单位毫秒connectionManager.getParams().setConnectionTimeout(3000);//读取超时,单位毫秒connectionManager.getParams().setSoTimeout(60000);//设置获取内容编码connectionManager.getParams().setParameter(HttpMethodParams.HTTP_CONTENT_CHARSET,urlCharset);client = new HttpClient(new HttpClientParams(),connectionManager);post = new PostMethod(targetUrl);//设置请求参数的编码post.getParams().setContentCharset(urlCharset);//服务端完成返回后，主动关闭链接post.setRequestHeader("Connection","close");if(params != null){nameValuePairArr = new NameValuePair[params.size()];Set key = params.keySet();Iterator keyIte = key.iterator();int index = 0;while(keyIte.hasNext()){Object paramName = keyIte.next();Object paramValue = params.get(paramName);if(paramName instanceof String && paramValue instanceof String){NameValuePair pair = new NameValuePair((String)paramName,(String)paramValue);nameValuePairArr[index] = pair;index++;}}post.addParameters(nameValuePairArr);}int sendStatus = client.executeMethod(post);if(sendStatus == HttpStatus.SC_OK){System.out.println("HttpClientUtil.setPostRequest()-responseType:"+responseType);if(StringUtils.equals(TYPE_STRING,responseType)){responseResult = post.getResponseBodyAsString();}else if(StringUtils.equals(TYPE_BYTEARRAY,responseType)){responseResult = post.getResponseBody();}else if(StringUtils.equals(TYPE_STREAM,responseType)){InputStream tempStream = post.getResponseBodyAsStream();byte[] temp = new byte[1024];int index = -1;while((index = tempStream.read(temp)) != -1){outputStream.write(temp);}}}else{System.err.println("***************************");System.err.println("HttpClientUtil.setPostRequest()-请求url："+targetUrl+" 出错\n请求参数有："+JsonUtil.java2JsonStr(params)+"！！！");System.err.println("***************************");}}catch(Exception e){e.printStackTrace();}finally{//释放链接if(post != null){post.releaseConnection();}//关闭链接if(connectionManager != null){connectionManager.shutdown();}}return responseResult;}/** * 测试方法 * @param args */public static void main(String[] args)throws Exception{//String url = "http://192.168.33.33:7001/rworg/rworg/poPublic.do?method=portalSearch";String url = "http://localhost:9080/platform/baseService/um/dataSync.do";Map params = new HashMap();params.put("method","saveUser");params.put("userAccount","admin");params.put("keyWords","111");params.put("type","中午 我的是");HttpClientUtil util = HttpClientUtil.getInstance("GBK");String resultStr = util.getResponseBodyAsString(url,params);byte[] resultArr = util.getResponseBodyAsByteArray(url,params);File file = new File("D:\\result.txt");FileOutputStream out = new FileOutputStream(file);util.getResponseBodyAsStream(url,params,out);System.out.println("HttpClientUtil.main()-result:"+resultStr);if(resultArr != null){System.out.println("HttpClientUtil.main()-result:"+new String(resultArr));}}}

需要注意的两个问题：

1、代码中使用的http-client版本是3.1，这个比较重要，直接使用该工具类还需要增加其他的依赖包（commons-codec.jar和commons-logging）

2、该版本的源码中，可以将连接超时和读取超时设计成可配置，在使用工具类的时候，能够依据实际的情况设置连接超时和读取超时的具体值。