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java网络编程中向指定URL发送GET POST请求示例

运维开发网 https://www.qedev.com 2020-03-07 09:57 出处:网络 作者: 网络整理
复制代码 代码如下:import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.PrintWriter;import java.net.HttpURLConnection;imp
复制代码 代码如下:

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.net.HttpURLConnection;

import java.net.URL;

import java.net.URLConnection;

import java.util.List;

import java.util.Map;

public class HttpRequest {

    /**

     * 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结果

     */

    public static String sendGet(String url, String param) {

        String result = "";

        BufferedReader in = null;

        try {

            String urlNameString = url + "?" + param;

            URL realUrl = new URL(urlNameString);

            // 打开和URL之间的连接

            URLConnection connection = realUrl.openConnection();

            // 设置通用的请求属性

            connection.setRequestProperty("accept", "*/*");

            connection.setRequestProperty("connection", "Keep-Alive");

            connection.setRequestProperty("user-agent",

                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");

            // 建立实际的连接

            connection.connect();

            // 获取所有响应头字段

            /*

             * Map<String, List<String>> map = connection.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(

                    connection.getInputStream()));

            String line;

            while ((line = in.readLine()) != null) {

                result += 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 (Exception e2) {

                e2.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 所代表远程资源的响应结果

     */

    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 += 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;

    }

}

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