[JAVA] HTTP请求,返回响应内容，实例及应用

JDK 中提供了一些对无状态协议请求（HTTP ）的支持，下面我就将我所写的一个小例子（组件）进行描述：

首先让我们先构建一个请求类（HttpRequester ）。

该类封装了 JAVA 实现简单请求的代码，如下：

import java.io.BufferedReader;  
import java.io.IOException;  
import java.io.InputStream;  
import java.io.InputStreamReader;  
import java.net.HttpURLConnection;  
import java.net.URL;  
import java.nio.charset.Charset;  
import java.util.Map;  
import java.util.Vector;  
   
/** 
 * HTTP请求对象 
 *  
 * @author YYmmiinngg 
 */  
public class HttpRequester {  
    private String defaultContentEncoding;  
   
    public HttpRequester() {  
        this.defaultContentEncoding = Charset.defaultCharset().name();  
    }  
   
    /** 
     * 发送GET请求 
     *  
     * @param urlString 
     *            URL地址 
     * @return 响应对象 
     * @throws IOException 
     */  
    public HttpRespons sendGet(String urlString) throws IOException {  
        return this.send(urlString, "GET", null, null);  
    }  
   
    /** 
     * 发送GET请求 
     *  
     * @param urlString 
     *            URL地址 
     * @param params 
     *            参数集合 
     * @return 响应对象 
     * @throws IOException 
     */  
    public HttpRespons sendGet(String urlString, Map<String, String> params)  
            throws IOException {  
        return this.send(urlString, "GET", params, null);  
    }  
   
    /** 
     * 发送GET请求 
     *  
     * @param urlString 
     *            URL地址 
     * @param params 
     *            参数集合 
     * @param propertys 
     *            请求属性 
     * @return 响应对象 
     * @throws IOException 
     */  
    public HttpRespons sendGet(String urlString, Map<String, String> params,  
            Map<String, String> propertys) throws IOException {  
        return this.send(urlString, "GET", params, propertys);  
    }  
   
    /** 
     * 发送POST请求 
     *  
     * @param urlString 
     *            URL地址 
     * @return 响应对象 
     * @throws IOException 
     */  
    public HttpRespons sendPost(String urlString) throws IOException {  
        return this.send(urlString, "POST", null, null);  
    }  
   
    /** 
     * 发送POST请求 
     *  
     * @param urlString 
     *            URL地址 
     * @param params 
     *            参数集合 
     * @return 响应对象 
     * @throws IOException 
     */  
    public HttpRespons sendPost(String urlString, Map<String, String> params)  
            throws IOException {  
        return this.send(urlString, "POST", params, null);  
    }  
   
    /** 
     * 发送POST请求 
     *  
     * @param urlString 
     *            URL地址 
     * @param params 
     *            参数集合 
     * @param propertys 
     *            请求属性 
     * @return 响应对象 
     * @throws IOException 
     */  
    public HttpRespons sendPost(String urlString, Map<String, String> params,  
            Map<String, String> propertys) throws IOException {  
        return this.send(urlString, "POST", params, propertys);  
    }  
   
    /** 
     * 发送HTTP请求 
     *  
     * @param urlString 
     * @return 响映对象 
     * @throws IOException 
     */  
    private HttpRespons send(String urlString, String method,  
            Map<String, String> parameters, Map<String, String> propertys)  
            throws IOException {  
        HttpURLConnection urlConnection = null;  
   
        if (method.equalsIgnoreCase("GET") && parameters != null) {  
            StringBuffer param = new StringBuffer();  
            int i = 0;  
            for (String key : parameters.keySet()) {  
                if (i == 0)  
                    param.append("?");  
                else  
                    param.append("&");  
                param.append(key).append("=").append(parameters.get(key));  
                i++;  
            }  
            urlString += param;  
        }  
        URL url = new URL(urlString);  
        urlConnection = (HttpURLConnection) url.openConnection();  
   
        urlConnection.setRequestMethod(method);  
        urlConnection.setDoOutput(true);  
        urlConnection.setDoInput(true);  
        urlConnection.setUseCaches(false);  
   
        if (propertys != null)  
            for (String key : propertys.keySet()) {  
                urlConnection.addRequestProperty(key, propertys.get(key));  
            }  
   
        if (method.equalsIgnoreCase("POST") && parameters != null) {  
            StringBuffer param = new StringBuffer();  
            for (String key : parameters.keySet()) {  
                param.append("&");  
                param.append(key).append("=").append(parameters.get(key));  
            }  
            urlConnection.getOutputStream().write(param.toString().getBytes());  
            urlConnection.getOutputStream().flush();  
            urlConnection.getOutputStream().close();  
        }  
   
        return this.makeContent(urlString, urlConnection);  
    }  
   
    /** 
     * 得到响应对象 
     *  
     * @param urlConnection 
     * @return 响应对象 
     * @throws IOException 
     */  
    private HttpRespons makeContent(String urlString,  
            HttpURLConnection urlConnection) throws IOException {  
        HttpRespons httpResponser = new HttpRespons();  
        try {  
            InputStream in = urlConnection.getInputStream();  
            BufferedReader bufferedReader = new BufferedReader(  
                    new InputStreamReader(in));  
            httpResponser.contentCollection = new Vector<String>();  
            StringBuffer temp = new StringBuffer();  
            String line = bufferedReader.readLine();  
            while (line != null) {  
                httpResponser.contentCollection.add(line);  
                temp.append(line).append("
");  
                line = bufferedReader.readLine();  
            }  
            bufferedReader.close();  
   
            String ecod = urlConnection.getContentEncoding();  
            if (ecod == null)  
                ecod = this.defaultContentEncoding;  
   
            httpResponser.urlString = urlString;  
   
            httpResponser.defaultPort = urlConnection.getURL().getDefaultPort();  
            httpResponser.file = urlConnection.getURL().getFile();  
            httpResponser.host = urlConnection.getURL().getHost();  
            httpResponser.path = urlConnection.getURL().getPath();  
            httpResponser.port = urlConnection.getURL().getPort();  
            httpResponser.protocol = urlConnection.getURL().getProtocol();  
            httpResponser.query = urlConnection.getURL().getQuery();  
            httpResponser.ref = urlConnection.getURL().getRef();  
            httpResponser.userInfo = urlConnection.getURL().getUserInfo();  
   
            httpResponser.content = new String(temp.toString().getBytes(), ecod);  
            httpResponser.contentEncoding = ecod;  
            httpResponser.code = urlConnection.getResponseCode();  
            httpResponser.message = urlConnection.getResponseMessage();  
            httpResponser.contentType = urlConnection.getContentType();  
            httpResponser.method = urlConnection.getRequestMethod();  
            httpResponser.connectTimeout = urlConnection.getConnectTimeout();  
            httpResponser.readTimeout = urlConnection.getReadTimeout();  
   
            return httpResponser;  
        } catch (IOException e) {  
            throw e;  
        } finally {  
            if (urlConnection != null)  
                urlConnection.disconnect();  
        }  
    }  
   
    /** 
     * 默认的响应字符集 
     */  
    public String getDefaultContentEncoding() {  
        return this.defaultContentEncoding;  
    }  
   
    /** 
     * 设置默认的响应字符集 
     */  
    public void setDefaultContentEncoding(String defaultContentEncoding) {  
        this.defaultContentEncoding = defaultContentEncoding;  
    }  
}

其次我们来看看响应对象（HttpRespons ）。 响应对象其实只是一个数据BEAN ，由此来封装请求响应的结果数据，如下：

import java.util.Vector;  
       
    /** 
     * 响应对象 
     */  
    public class HttpRespons {  
       
        String urlString;  
       
        int defaultPort;  
       
        String file;  
       
        String host;  
       
        String path;  
       
        int port;  
       
        String protocol;  
       
        String query;  
       
        String ref;  
       
        String userInfo;  
       
        String contentEncoding;  
       
        String content;  
       
        String contentType;  
       
        int code;  
       
        String message;  
       
        String method;  
       
        int connectTimeout;  
       
        int readTimeout;  
       
        Vector<String> contentCollection;  
       
        public String getContent() {  
            return content;  
        }  
       
        public String getContentType() {  
            return contentType;  
        }  
       
        public int getCode() {  
            return code;  
        }  
       
        public String getMessage() {  
            return message;  
        }  
       
        public Vector<String> getContentCollection() {  
            return contentCollection;  
        }  
       
        public String getContentEncoding() {  
            return contentEncoding;  
        }  
       
        public String getMethod() {  
            return method;  
        }  
       
        public int getConnectTimeout() {  
            return connectTimeout;  
        }  
       
        public int getReadTimeout() {  
            return readTimeout;  
        }  
       
        public String getUrlString() {  
            return urlString;  
        }  
       
        public int getDefaultPort() {  
            return defaultPort;  
        }  
       
        public String getFile() {  
            return file;  
        }  
       
        public String getHost() {  
            return host;  
        }  
       
        public String getPath() {  
            return path;  
        }  
       
        public int getPort() {  
            return port;  
        }  
       
        public String getProtocol() {  
            return protocol;  
        }  
       
        public String getQuery() {  
            return query;  
        }  
       
        public String getRef() {  
            return ref;  
        }  
       
        public String getUserInfo() {  
            return userInfo;  
        }  
       
    }

最后，让我们写一个应用类，测试以上代码是否正确

import com.yao.http.HttpRequester;  
import com.yao.http.HttpRespons;  
       
    public class Test {  
        public static void main(String[] args) {  
            try {  
                HttpRequester request = new HttpRequester();  
                HttpRespons hr = request.sendGet("http://www.csdn.net");  
       
                System.out.println(hr.getUrlString());  
                System.out.println(hr.getProtocol());  
                System.out.println(hr.getHost());  
                System.out.println(hr.getPort());  
                System.out.println(hr.getContentEncoding());  
                System.out.println(hr.getMethod());  
                  
                System.out.println(hr.getContent());  
       
            } catch (Exception e) {  
                e.printStackTrace();  
            }  
        }  
    }