JAVA通过HTTP访问：Post+Get方式

public class TestGetPost {
    /**
     * 向指定URL发送GET方法的请求
     * @param url 发送请求的URL
     * @param param 请求参数，请求参数应该是name1=value1&name2=value2的形式。
     * @return URL所代表远程资源的响应
     */

    public static String sendGet(String url, String param) {
        String result = "";
        BufferedReader in = null;
        try {
            String urlName = url + "?" + param;
            URL realUrl = new URL(urlName);
            //打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            //设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent",
                "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
            //建立实际的连接
            conn.connect();
            //获取所有响应头字段
            Map < String, List < String >> map = conn.getHeaderFields();
            //遍历所有的响应头字段
            for (String key: map.keySet()) {
                System.out.println(key + "--->" + map.get(key));
            }
            //定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in .readLine()) != null) {
                result += "/n" + line;
            }
        } catch (Exception e) {
            System.out.println("发送GET请求出现异常！" + e);
            e.printStackTrace();
        }
        //使用finally块来关闭输入流
        finally {
            try {
                if ( in != null) { in .close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        return result;
    }
    /**
     * 向指定URL发送POST方法的请求
     * @param url 发送请求的URL
     * @param param 请求参数，请求参数应该是name1=value1&name2=value2的形式。
     * @return URL所代表远程资源的响应
     */
    public static String sendPost(String url, String param) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            //打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            //设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent",
                "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
            //发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            //获取URLConnection对象对应的输出流
            out = new PrintWriter(conn.getOutputStream());
            //发送请求参数
            out.print(param);
            //flush输出流的缓冲
            out.flush();
            //定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(
                new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in .readLine()) != null) {
                result += "/n" + line;
            }
        } catch (Exception e) {
            System.out.println("发送POST请求出现异常！" + e);
            e.printStackTrace();
        }
        //使用finally块来关闭输出流、输入流
        finally {
            try {
                if (out != null) {
                    out.close();
                }
                if ( in != null) { in .close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        return result;
    }


    //提供主方法，测试发送GET请求和POST请求
    public static void main(String args[]) {
        //发送GET请求
        String s = TestGetPost.sendGet("http://localhost:8888/abc/login.jsp", null);
        System.out.println(s);
        //发送POST请求
        String s1 = TestGetPost.sendPost(http: //localhost:8888/abc/a.jsp ,
            "user=李刚&pass=abc");
        System.out.println(s1);
    }
}