基于HttpClient的java后台访问URL

痛定思痛。 2022-08-09 09:38 186阅读 0赞

**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);
    	}
    }