Contents

• 访问互联网资源
  • 使用HttpURLConnection发送GET请求
  • 使用HttpURLConnection发送POST请求
  • 实例：Downloader

21.5. 访问互联网资源

21.5.1. 使用HttpURLConnection发送GET请求

package com.a51work.cn;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class Get_network {

    // Web服务网址
//    static String urlString = "http://www.51work6.com/service/mynotes/WebService.php?"
//            + "email=<1879324764@qq.com>&type=JSON&action=query";
    static String urlString = "http://www.xz577.com/";

    public static void main(String[] args) {
        BufferedReader br = null;
        HttpURLConnection conn = null;
        try {
            URL reqURL = new URL(urlString);
            conn = (HttpURLConnection) reqURL.openConnection();
            conn.setRequestMethod("GET");

            // 打开网络通信输入流
            InputStream is = conn.getInputStream();
            // 通过is创建InputStreamReader对象
            InputStreamReader isr = new InputStreamReader(is, "utf-8");
            // 通过isr创建BufferedReader对象
            br = new BufferedReader(isr);

            StringBuilder sb = new StringBuilder();
            String line = br.readLine();
            while (line != null) {
                sb.append(line);
                line = br.readLine();
            }
            // 日志输出
            System.out.println(sb);

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (conn != null) {
                // 断开连接
                conn.disconnect();
            }

            if (br != null) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

21.5.2. 使用HttpURLConnection发送POST请求

package com.a51work.cn;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

public class POST_network {
    // Web服务网址
    static String urlString = "http://www.51work6.com/service/mynotes/WebService.php";

    public static void main(String[] args) {
        BufferedReader br = null;
        HttpURLConnection conn = null;
        try {
            URL reqURL = new URL(urlString);
            conn = (HttpURLConnection) reqURL.openConnection();
            conn.setRequestMethod("POST");
            conn.setDoOutput(true);
            String param = String.format("email=%s&type=%s&action=%s",
                    "<1879324764@qq.com>", "JSON", "query");
            // 设置参数
            DataOutputStream dStream = new DataOutputStream(conn.getOutputStream());
            dStream.writeBytes(param);
            dStream.close();
            // 打开网络通信输入流
            InputStream is = conn.getInputStream();
            // 通过is创建InputStreamReader对象
            InputStreamReader isr = new InputStreamReader(is, "utf-8");
            // 通过isr创建BufferedReader对象
            br = new BufferedReader(isr);
            StringBuilder sb = new StringBuilder();
            String line = br.readLine();
            while (line != null) {
                sb.append(line);
                line = br.readLine();
            }
            // 日志输出
            System.out.println(sb);

        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            if (conn != null){
                conn.disconnect();
            }
            if (br != null){
            try {
                br.close();
            }catch (IOException e){
                e.printStackTrace();
            }
        }
    }
    }
}

21.5.3. 实例：Downloader

package com.a51work.cn;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

public class Downloader {
    // Web服务网址
    private static String urlString = "http://www.51work6.com/" + "template/veikei_dz_com_20130920_color/images/logo.png";

    public static void main(String[] args) {
        download();
    }

    // 下载方法
    public static void download() {
        HttpURLConnection conn = null;
        try {
            // 创建URL对象
            URL reqURL = new URL(urlString);
            // 打开连接
            conn = (HttpURLConnection) reqURL.openConnection();
            try (// 从连接对象获得输入流
                 InputStream is = conn.getInputStream();
                 BufferedInputStream bin = new BufferedInputStream(is);
                 // 创建文件输出流
                 OutputStream os = new FileOutputStream("./download.png");
                 BufferedOutputStream bout = new BufferedOutputStream(os);) {
                byte[] buffer = new byte[1024];
                int bytesRead = bin.read(buffer);
                while (bytesRead != -1) {
                    bout.write(buffer, 0, bytesRead);
                    bytesRead = bin.read(buffer);
                }
            } catch (IOException e) {
            }
            System.out.println("下载完成。");
        } catch (IOException e) {
        } finally {
            if (conn != null) {
                conn.disconnect();
            }

        }
    }
}