基于HttpClient的java后台访问URL

写支付相关东西遇到需要在后台访问url，搜了搜找到一篇不错的文章，收藏下来以留后用。

httpUtils.java中有两个公共的静态方法，一个是URLPost，另一个是URLGet，一目了然，前者是提供POST方式提交数据的，后者是提供GET方式提交数据的。其中所需要传送的数据以Map的方式传入，剩下的工作就交给我这个HttpUtils吧！当然如果Http服务器端对所提交的数据的编码有要求的话，也没问题，你可以传入UTF-8或者GBK，当然大家还可自行增加。

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.MultiThreadedHttpConnectionManager;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
* HTTP工具类
*
* @author lixiangyang
*
*/
public class HttpUtils {

private static Log log = LogFactory.getLog(HttpUtils.class);
/**
* 定义编码格式 UTF-8
*/
public static final String URL_PARAM_DECODECHARSET_UTF8 = "UTF-8";
/**
* 定义编码格式 GBK
*/
public static final String URL_PARAM_DECODECHARSET_GBK = "GBK";
private static final String URL_PARAM_CONNECT_FLAG = "&";
private static final String EMPTY = "";
private static MultiThreadedHttpConnectionManager connectionManager = null;
private static int connectionTimeOut = 25000;
private static int socketTimeOut = 25000;
private static int maxConnectionPerHost = 20;
private static int maxTotalConnections = 20;
private static HttpClient client;
static{
connectionManager = new MultiThreadedHttpConnectionManager();
connectionManager.getParams().setConnectionTimeout(connectionTimeOut);
connectionManager.getParams().setSoTimeout(socketTimeOut);
connectionManager.getParams().setDefaultMaxConnectionsPerHost(maxConnectionPerHost);
connectionManager.getParams().setMaxTotalConnections(maxTotalConnections);
client = new HttpClient(connectionManager);
}
/**
* POST方式提交数据
* @param url
* 			待请求的URL
* @param params
* 			要提交的数据
* @param enc
* 			编码
* @return
* 			响应结果
* @throws IOException
* 			IO异常
*/
public static String URLPost(String url, Map<String, String> params, String enc){
String response = EMPTY;
PostMethod postMethod = null;
try {
postMethod = new PostMethod(url);
postMethod.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=" + enc);
//将表单的值放入postMethod中
Set<String> keySet = params.keySet();
for(String key : keySet){
String value = params.get(key);
postMethod.addParameter(key, value);
}
//执行postMethod
int statusCode = client.executeMethod(postMethod);
if(statusCode == HttpStatus.SC_OK) {
response = postMethod.getResponseBodyAsString();
}else{
log.error("响应状态码 = " + postMethod.getStatusCode());
}
}catch(HttpException e){
log.error("发生致命的异常，可能是协议不对或者返回的内容有问题", e);
e.printStackTrace();
}catch(IOException e){
log.error("发生网络异常", e);
e.printStackTrace();
}finally{
if(postMethod != null){
postMethod.releaseConnection();
postMethod = null;
}
}
return response;
}

/**
* GET方式提交数据
* @param url
* 			待请求的URL
* @param params
* 			要提交的数据
* @param enc
* 			编码
* @return
* 			响应结果
* @throws IOException
* 			IO异常
*/
public static String URLGet(String url, Map<String, String> params, String enc){
String response = EMPTY;
GetMethod getMethod = null;
StringBuffer strtTotalURL = new StringBuffer(EMPTY);

if(strtTotalURL.indexOf("?") == -1) {
strtTotalURL.append(url).append("?").append(getUrl(params, enc));
} else {
strtTotalURL.append(url).append("&").append(getUrl(params, enc));
}
log.debug("GET请求URL = \n" + strtTotalURL.toString());

try {
getMethod = new GetMethod(strtTotalURL.toString());
getMethod.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=" + enc);
//执行getMethod
int statusCode = client.executeMethod(getMethod);
if(statusCode == HttpStatus.SC_OK) {
response = getMethod.getResponseBodyAsString();
}else{
log.debug("响应状态码 = " + getMethod.getStatusCode());
}
}catch(HttpException e){
log.error("发生致命的异常，可能是协议不对或者返回的内容有问题", e);
e.printStackTrace();
}catch(IOException e){
log.error("发生网络异常", e);
e.printStackTrace();
}finally{
if(getMethod != null){
getMethod.releaseConnection();
getMethod = null;
}
}
return response;
}

/**
* 据Map生成URL字符串
* @param map
* 			Map
* @param valueEnc
* 			URL编码
* @return
* 			URL
*/
private static String getUrl(Map<String, String> map, String valueEnc) {

if (null == map || map.keySet().size() == 0) {
return (EMPTY);
}
StringBuffer url = new StringBuffer();
Set<String> keys = map.keySet();
for (Iterator<String> it = keys.iterator(); it.hasNext();) {
String key = it.next();
if (map.containsKey(key)) {
String val = map.get(key);
String str = val != null ? val : EMPTY;
try {
str = URLEncoder.encode(str, valueEnc);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
url.append(key).append("=").append(str).append(URL_PARAM_CONNECT_FLAG);
}
}
String strURL = EMPTY;
strURL = url.toString();
if (URL_PARAM_CONNECT_FLAG.equals(EMPTY + strURL.charAt(strURL.length() - 1))) {
strURL = strURL.substring(0, strURL.length() - 1);
}
return (strURL);
}
}