[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("\r\n");
                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();
            }
        }
    }