Java调用Http接口(2)--HttpURLConnection调用Http接口

其他 2019-11-23 11:34:25 阅读次数: 0

HttpURLConnection是JDK自身提供的网络类，不需要引入额外的jar包。文中所使用到的软件版本：Java 1.8.0_191。

1、GET请求

public static void get() {
    HttpURLConnection connection = null;
    try {
        String requestPath = "http://localhost:8080/webframe/demo/test/getUser?userId=1000&userName=" + URLEncoder.encode("李白", "utf-8");
        URL url = new URL(requestPath);
        //设置代理
        //InetSocketAddress addr = new InetSocketAddress("127.0.0.1", 8888);  
        //Proxy proxy = new Proxy(Proxy.Type.HTTP, addr);
        //connection = (HttpURLConnection)url.openConnection(proxy);
        
        connection = (HttpURLConnection)url.openConnection();
        connection.setRequestMethod("GET");
        connection.connect();
        
        if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
            byte[] b = getBytesFromInputStream(connection.getInputStream());
            String back = new String(b);
            System.out.println("GET返回结果：" + back);
        } else {
            System.out.println("GET请求状态码：" + connection.getResponseCode());
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        connection.disconnect();
    }
}

2、POST请求(发送键值对数据）

public static void post() {
    HttpURLConnection connection = null;
    try {
        String requestPath = "http://localhost:8080/webframe/demo/test/getUser";
        URL url = new URL(requestPath);
        connection = (HttpURLConnection)url.openConnection();
        connection.setRequestMethod("POST");
        connection.setDoOutput(true);
        connection.connect();
        
        String param = "userId=1000&userName=李白";
        setBytesToOutputStream(connection.getOutputStream(), param.getBytes());
        
        if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
            byte[] b = getBytesFromInputStream(connection.getInputStream());
            String back = new String(b);
            System.out.println("POST返回结果：" + back);
        } else {
            System.out.println("POST请求状态码：" + connection.getResponseCode());
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        connection.disconnect();
    }
}

3、POST请求(发送JSON数据）

public static void post2() {
    HttpURLConnection connection = null;
    try {
        String requestPath = "http://localhost:8080/webframe/demo/test/addUser";
        URL url = new URL(requestPath);
        connection = (HttpURLConnection)url.openConnection();
        connection.setRequestMethod("POST");
        connection.setDoOutput(true);
        connection.setRequestProperty("Content-type", "application/json");
        connection.connect();
        
        String param = "{\"userId\": \"1001\",\"userName\":\"杜甫\"}";
        setBytesToOutputStream(connection.getOutputStream(), param.getBytes());
        
        if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
            byte[] b = getBytesFromInputStream(connection.getInputStream());
            String back = new String(b);
            System.out.println("POST2返回结果：" + back);
        } else {
            System.out.println("POST2请求状态码：" + connection.getResponseCode());
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        connection.disconnect();
    }
}

4、上传文件及发送键值对数据

4.1、分析数据结构

通过抓包工具分析页面表单上传文件的过程，可以看出传输数据的结构：

 

4.2、根据分析出的数据结构编写代码

public static void multi() {
    String BOUNDARY = java.util.UUID.randomUUID().toString();
    String TWO_HYPHENS = "--";
    String LINE_END = "\r\n";
    HttpURLConnection connection = null;
    try {
        String requestPath = "http://localhost:8080/webframe/demo/test/multi";
        URL url = new URL(requestPath);
        connection = (HttpURLConnection)url.openConnection();
        connection.setRequestMethod("POST");
        connection.setDoOutput(true);
        connection.setDoInput(true);
        connection.setRequestProperty("Content-type", "multipart/form-data; BOUNDARY=" + BOUNDARY);
        connection.connect();
        
        StringBuffer sb = new StringBuffer();
        //封装键值对数据1
        sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
        sb.append("Content-Disposition: form-data; name=\"param1\"").append(LINE_END);
        sb.append(LINE_END);
        sb.append("参数1").append(LINE_END);
        
        //封装键值对数据2
        sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
        sb.append("Content-Disposition: form-data; name=\"param2\"").append(LINE_END);
        sb.append(LINE_END);
        sb.append("参数2").append(LINE_END);
        
        //封装文件数据
        sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
        sb.append("Content-Disposition: form-data; name=\"file\"; filename=\"a.jpg\"").append(LINE_END);
        sb.append("Content-Type: file/*").append(LINE_END);
        sb.append(LINE_END);

        setBytesToOutputStream(connection.getOutputStream(), sb.toString().getBytes());

        FileInputStream fileInputStream = new FileInputStream("d:/a.jpg");
        setBytesToOutputStream(connection.getOutputStream(), fileInputStream);
        
        //写入标记结束位
        byte[] endData = (LINE_END + TWO_HYPHENS + BOUNDARY + TWO_HYPHENS + LINE_END).getBytes();
        setBytesToOutputStream(connection.getOutputStream(), endData);
        
        if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
            byte[] b = getBytesFromInputStream(connection.getInputStream());
            String back = new String(b);
            System.out.println("upload返回结果：" + back);
        } else {
            System.out.println("upload请求状态码：" + connection.getResponseCode());
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        connection.disconnect();
    }
}

4.3、上传文件方法变通

这种方式上传文件完全是模拟页面的提交行为来编码的，比较繁琐。可以把文件转成字符串，然后通过键值对传给服务端，服务端执行相反的过程来存储文件：

客户端：文件-> 字节数组->Base64字符串

服务端：Base64字符串-> 字节数组->文件

5、完整例子

package com.inspur.http;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.URL;
import java.net.URLEncoder;

/**
 * 
 * 通过HttpURLConnection调用Http接口
 *
 */
public class HttpURLConnectionCase {
    /**
     * GET请求
     */
    public static void get() {
        HttpURLConnection connection = null;
        try {
            String requestPath = "http://localhost:8080/webframe/demo/test/getUser?userId=1000&userName=" + URLEncoder.encode("李白", "utf-8");
            URL url = new URL(requestPath);
            //设置代理
            //InetSocketAddress addr = new InetSocketAddress("127.0.0.1", 8888);  
            //Proxy proxy = new Proxy(Proxy.Type.HTTP, addr);
            //connection = (HttpURLConnection)url.openConnection(proxy);
            
            connection = (HttpURLConnection)url.openConnection();
            connection.setRequestMethod("GET");
            connection.connect();
            
            if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                byte[] b = getBytesFromInputStream(connection.getInputStream());
                String back = new String(b);
                System.out.println("GET返回结果：" + back);
            } else {
                System.out.println("GET请求状态码：" + connection.getResponseCode());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            connection.disconnect();
        }
    }
    
    /**
     * POST请求，发送键值对数据
     */
    public static void post() {
        HttpURLConnection connection = null;
        try {
            String requestPath = "http://localhost:8080/webframe/demo/test/getUser";
            URL url = new URL(requestPath);
            connection = (HttpURLConnection)url.openConnection();
            connection.setRequestMethod("POST");
            connection.setDoOutput(true);
            connection.connect();
            
            String param = "userId=1000&userName=李白";
            setBytesToOutputStream(connection.getOutputStream(), param.getBytes());
            
            if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                byte[] b = getBytesFromInputStream(connection.getInputStream());
                String back = new String(b);
                System.out.println("POST返回结果：" + back);
            } else {
                System.out.println("POST请求状态码：" + connection.getResponseCode());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            connection.disconnect();
        }
    }
    
    /**
     * POST请求，发送json格式数据
     */
    public static void post2() {
        HttpURLConnection connection = null;
        try {
            String requestPath = "http://localhost:8080/webframe/demo/test/addUser";
            URL url = new URL(requestPath);
            connection = (HttpURLConnection)url.openConnection();
            connection.setRequestMethod("POST");
            connection.setDoOutput(true);
            connection.setRequestProperty("Content-type", "application/json");
            connection.connect();
            
            String param = "{\"userId\": \"1001\",\"userName\":\"杜甫\"}";
            setBytesToOutputStream(connection.getOutputStream(), param.getBytes());
            
            if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                byte[] b = getBytesFromInputStream(connection.getInputStream());
                String back = new String(b);
                System.out.println("POST2返回结果：" + back);
            } else {
                System.out.println("POST2请求状态码：" + connection.getResponseCode());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            connection.disconnect();
        }
    }
    
    /**
     * 上传文件及发送键值对数据
     */
    public static void multi() {
        String BOUNDARY = java.util.UUID.randomUUID().toString();
        String TWO_HYPHENS = "--";
        String LINE_END = "\r\n";
        HttpURLConnection connection = null;
        try {
            String requestPath = "http://localhost:8080/webframe/demo/test/multi";
            URL url = new URL(requestPath);
            connection = (HttpURLConnection)url.openConnection();
            connection.setRequestMethod("POST");
            connection.setDoOutput(true);
            connection.setDoInput(true);
            connection.setRequestProperty("Content-type", "multipart/form-data; BOUNDARY=" + BOUNDARY);
            connection.connect();
            
            StringBuffer sb = new StringBuffer();
            //封装键值对数据1
            sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
            sb.append("Content-Disposition: form-data; name=\"param1\"").append(LINE_END);
            sb.append(LINE_END);
            sb.append("参数1").append(LINE_END);
            
            //封装键值对数据2
            sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
            sb.append("Content-Disposition: form-data; name=\"param2\"").append(LINE_END);
            sb.append(LINE_END);
            sb.append("参数2").append(LINE_END);
            
            //封装文件数据
            sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
            sb.append("Content-Disposition: form-data; name=\"file\"; filename=\"a.jpg\"").append(LINE_END);
            sb.append("Content-Type: file/*").append(LINE_END);
            sb.append(LINE_END);

            setBytesToOutputStream(connection.getOutputStream(), sb.toString().getBytes());

            FileInputStream fileInputStream = new FileInputStream("d:/a.jpg");
            setBytesToOutputStream(connection.getOutputStream(), fileInputStream);
            
            //写入标记结束位
            byte[] endData = (LINE_END + TWO_HYPHENS + BOUNDARY + TWO_HYPHENS + LINE_END).getBytes();
            setBytesToOutputStream(connection.getOutputStream(), endData);
            
            if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                byte[] b = getBytesFromInputStream(connection.getInputStream());
                String back = new String(b);
                System.out.println("upload返回结果：" + back);
            } else {
                System.out.println("upload请求状态码：" + connection.getResponseCode());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            connection.disconnect();
        }
    }
    
    
    /**
     * 从输入流获取数据
     * @param in
     * @return
     * @throws IOException
     */
    private static byte[] getBytesFromInputStream(InputStream in) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] b = new byte[1024];
        int len;
        while ((len = in.read(b)) != -1) {
            baos.write(b, 0, len);
        }
        byte[] bytes = baos.toByteArray();
        baos.close();
        in.close();
        return bytes;
    }
    
    /**
     * 向输入流发送数据
     * @param out
     * @param bytes
     * @throws IOException
     */
    private static void setBytesToOutputStream(OutputStream out, byte[] bytes) throws IOException {
        ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
        byte[] b = new byte[1024];
        int len;
        while ((len = bais.read(b)) != -1) {
            out.write(b, 0, len);
        }
        out.flush();
    }
    
    /**
     * 向输入流发送数据
     * @param out
     * @param bytes
     * @throws IOException
     */
    private static void setBytesToOutputStream(OutputStream out, InputStream data) throws IOException {
        byte[] b = new byte[1024];
        int len;
        while ((len = data.read(b)) != -1) {
            out.write(b, 0, len);
        }
        out.flush();
    }
    
    public static void main(String[] args) {
        get();
        post();
        post2();
        multi();
    }
}
View Code

猜你喜欢

转载自www.cnblogs.com/wuyongyin/p/11915587.html
今日推荐
TIOBE 5 月榜单：Fortran “复活”进入 Top 10
GCC 14.1 发布
面壁智能发布 Eurux-8x22B 开源大模型 —— 堪称「理科状元」
开源日报 | 谷歌扶持鸿蒙上位；开源Rabbit R1；Docker加持的安卓手机；微软的焦虑和野心；海尔电器把开放平台关了
中国码农的“35岁魔咒”
蘭雅 CorelDRAW 插件 2024.5.1 国际劳动节版，免费下载
Arc Browser for Windows 1.0 正式 GA
90后程序员开发视频搬运软件、不到一年获利超 700 万，结局很刑！
周排行
Java自定义时间格式
同步整形电路
在开发中最最最常用的字符串的属性大集合
Linux 查看端口占用并杀掉
Java基础四：ArrayList
多线程之死锁就是这么简单
mysql 基础命令集
awk 命令详解
Centos6.3编译安装nginx+php步骤
OCR （Optical Character Recognition，光学字符识别）
每日归档
更多
2024-05-08(42)
2024-05-07(14)
2024-05-06(40)
2024-05-05(0)
2024-05-04(7)
2024-05-03(19)
2024-05-02(0)
2024-05-01(4)
2024-04-30(1)
2024-04-29(40)

代码天地 © 2018 codetd.com

境外服务器   最新电视剧2022