• Java技能树-网络-HTTP-HttpURLConnection

    1 需求

    • 需求1：发送GET请求
    • 需求2：发送POST请求
    • 需求3：上传文件
    • 需求4：同时上传文件和参数

    2 接口

    Class HttpURLConnection


    java.lang.Object 
            java.net.URLConnection 
                    java.net.HttpURLConnection 

    public abstract class HttpURLConnection extends URLConnection

    Field Detail

    Constructor Detail

    • protected HttpURLConnection(URL u)


    Method Detail

    • public void setRequestMethod(String method) throws ProtocolException
    • public int getResponseCode() throws IOException

    Class URLConnection


    java.lang.Object 
            java.net.URLConnection


    public abstract class URLConnection extends Object

    Field Detail

    Constructor Detail

    Method Detail

    • public InputStream getInputStream() throws IOException
       

    Class URL


    java.lang.Object 
            java.net.URL


    public final class URL extends Object implements Serializable

    Constructor Detail

    • public URL(String spec) throws MalformedURLException

    Method Detail

    • public URLConnection openConnection() throws IOException
    • public URLConnection openConnection(Proxy proxy) throws IOException

    3 示例

    1. import java.io.BufferedReader;
    2. import java.io.IOException;
    3. import java.io.InputStream;
    4. import java.io.InputStreamReader;
    5. import java.net.HttpURLConnection;
    6. import java.net.URL;
    7.  
    8. /**
    9.  * 第一步，创建远程连接
    10.  * 第二步，设置连接方式（get、post、put。。。）
    11.  * 第三步，设置连接超时时间
    12.  * 第四步，设置响应读取时间
    13.  * 第五步，发起请求
    14.  * 第六步，获取请求数据
    15.  * 第七步，关闭连接
    16.  */
    17. public class Test {
    18.     public static void main(String[] args) {
    19.  
    20.         StringBuffer result = new StringBuffer();
    21.  
    22.         try {
    23.             // 创建连接
    24.             URL url = new URL("http://www.dvwa.com/login.php");
    25.             HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    26.             // 设置请求方式
    27.             connection.setRequestMethod("GET");
    28.             // 设置连接超时时间
    29.             connection.setReadTimeout(15000);
    30.  
    31.             // 开始连接
    32.             connection.connect();
    33.  
    34.             // 获取请求数据
    35.             if (connection.getResponseCode() == 200) {
    36.                 InputStream is = connection.getInputStream();
    37.                 if (is != null) {
    38.                     InputStreamReader ir = new InputStreamReader(is, "UTF-8");
    39.                     BufferedReader br = new BufferedReader(ir);
    40.                     String line = null;
    41.                     while ((line = br.readLine()) != null) {
    42.                         result.append(line);
    43.                     }
    44.                 }
    45.             }
    46.  
    47.             //
    48.             connection.disconnect();
    49.         } catch (IOException e) {
    50.             e.printStackTrace();
    51.         }
    52.  
    53.         System.out.println(result);
    54.     }
    55. }

    3.X 需求：文件上传

    1. import java.io.BufferedInputStream;
    2. import java.io.BufferedReader;
    3. import java.io.DataOutputStream;
    4. import java.io.File;
    5. import java.io.FileInputStream;
    6. import java.io.FileOutputStream;
    7. import java.io.IOException;
    8. import java.io.InputStream;
    9. import java.io.InputStreamReader;
    10. import java.io.OutputStream;
    11. import java.io.OutputStreamWriter;
    12. import java.net.HttpURLConnection;
    13. import java.net.MalformedURLException;
    14. import java.net.URL;
    15. import java.net.URLConnection;
    16. import java.util.Iterator;
    17. import java.util.Map;
    18.  
    19. /**
    20.  * Java原生的API可用于发送HTTP请求，即java.net.URL、java.net.URLConnection，这些API很好用、很常用，
    21.  * 但不够简便；
    22.  *
    23.  * 1.通过统一资源定位器（java.net.URL）获取连接器（java.net.URLConnection） 2.设置请求的参数 3.发送请求
    24.  * 4.以输入流的形式获取返回内容 5.关闭输入流
    25.  *
    26.  * @author H__D
    27.  *
    28.  */
    29. public class Test {
    30.  
    31.  
    32.     /**
    33.      * 多文件上传的方法
    34.      *
    35.      * @param actionUrl：上传的路径
    36.      * @param uploadFilePaths：需要上传的文件路径，数组
    37.      * @return
    38.      */
    39.     @SuppressWarnings("finally")
    40.     public static String uploadFile(String actionUrl, String[] uploadFilePaths) {
    41.         String end = "\r\n";
    42.         String twoHyphens = "--";
    43.         String boundary = "*****";
    44.  
    45.         DataOutputStream ds = null;
    46.         InputStream inputStream = null;
    47.         InputStreamReader inputStreamReader = null;
    48.         BufferedReader reader = null;
    49.         StringBuffer resultBuffer = new StringBuffer();
    50.         String tempLine = null;
    51.  
    52.         try {
    53.             // 统一资源
    54.             URL url = new URL(actionUrl);
    55.             // 连接类的父类，抽象类
    56.             URLConnection urlConnection = url.openConnection();
    57.             // http的连接类
    58.             HttpURLConnection httpURLConnection = (HttpURLConnection) urlConnection;
    59.  
    60.             // 设置是否从httpUrlConnection读入，默认情况下是true;
    61.             httpURLConnection.setDoInput(true);
    62.             // 设置是否向httpUrlConnection输出
    63.             httpURLConnection.setDoOutput(true);
    64.             // Post 请求不能使用缓存
    65.             httpURLConnection.setUseCaches(false);
    66.             // 设定请求的方法，默认是GET
    67.             httpURLConnection.setRequestMethod("POST");
    68.             // 设置字符编码连接参数
    69.             httpURLConnection.setRequestProperty("Connection", "Keep-Alive");
    70.             // 设置字符编码
    71.             httpURLConnection.setRequestProperty("Charset", "UTF-8");
    72.             // 设置请求内容类型
    73.             httpURLConnection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
    74.  
    75.             // 设置DataOutputStream
    76.             ds = new DataOutputStream(httpURLConnection.getOutputStream());
    77.             for (int i = 0; i < uploadFilePaths.length; i++) {
    78.                 String uploadFile = uploadFilePaths[i];
    79.                 String filename = uploadFile.substring(uploadFile.lastIndexOf("//") + 1);
    80.                 ds.writeBytes(twoHyphens + boundary + end);
    81.                 ds.writeBytes("Content-Disposition: form-data; " + "name=\"file" + i + "\";filename=\"" + filename
    82.                         + "\"" + end);
    83.                 ds.writeBytes(end);
    84.                 FileInputStream fStream = new FileInputStream(uploadFile);
    85.                 int bufferSize = 1024;
    86.                 byte[] buffer = new byte[bufferSize];
    87.                 int length = -1;
    88.                 while ((length = fStream.read(buffer)) != -1) {
    89.                     ds.write(buffer, 0, length);
    90.                 }
    91.                 ds.writeBytes(end);
    92.                 /* close streams */
    93.                 fStream.close();
    94.             }
    95.             ds.writeBytes(twoHyphens + boundary + twoHyphens + end);
    96.             /* close streams */
    97.             ds.flush();
    98.             if (httpURLConnection.getResponseCode() >= 300) {
    99.                 throw new Exception(
    100.                         "HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode());
    101.             }
    102.  
    103.             if (httpURLConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
    104.                 inputStream = httpURLConnection.getInputStream();
    105.                 inputStreamReader = new InputStreamReader(inputStream);
    106.                 reader = new BufferedReader(inputStreamReader);
    107.                 tempLine = null;
    108.                 resultBuffer = new StringBuffer();
    109.                 while ((tempLine = reader.readLine()) != null) {
    110.                     resultBuffer.append(tempLine);
    111.                     resultBuffer.append("\n");
    112.                 }
    113.             }
    114.  
    115.         } catch (Exception e) {
    116.             // TODO Auto-generated catch block
    117.             e.printStackTrace();
    118.         } finally {
    119.             if (ds != null) {
    120.                 try {
    121.                     ds.close();
    122.                 } catch (IOException e) {
    123.                     // TODO Auto-generated catch block
    124.                     e.printStackTrace();
    125.                 }
    126.             }
    127.             if (reader != null) {
    128.                 try {
    129.                     reader.close();
    130.                 } catch (IOException e) {
    131.                     // TODO Auto-generated catch block
    132.                     e.printStackTrace();
    133.                 }
    134.             }
    135.             if (inputStreamReader != null) {
    136.                 try {
    137.                     inputStreamReader.close();
    138.                 } catch (IOException e) {
    139.                     // TODO Auto-generated catch block
    140.                     e.printStackTrace();
    141.                 }
    142.             }
    143.             if (inputStream != null) {
    144.                 try {
    145.                     inputStream.close();
    146.                 } catch (IOException e) {
    147.                     // TODO Auto-generated catch block
    148.                     e.printStackTrace();
    149.                 }
    150.             }
    151.  
    152.             return resultBuffer.toString();
    153.         }
    154.     }
    155.  
    156.  
    157.     public static void main(String[] args) {
    158.  
    159.         // 上传文件测试
    160.         String str = uploadFile("http://localhost/MDM/upload.php",new String[] { "C:\\1.png" });
    161.         System.out.println(str);
    162.  
    163.  
    164.     }
    165.  
    166. }

    参考资料：

    通过HttpURLConnection 上传文件_pois的博客-CSDN博客_httpurlconnection 文件上传 

    HttpUrlConnection上传文件_三木神奇的博客-CSDN博客_httpurlconnection 文件上传

    4 参考资料

    java实现调用http请求的几种常见方式_qq_duhai的博客-CSDN博客_java http

    HttpUrlConnection上传文件_三木神奇的博客-CSDN博客_httpurlconnection 文件上传

    通过HttpURLConnection 上传文件_pois的博客-CSDN博客_httpurlconnection 文件上传

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  • 原文地址：https://blog.csdn.net/pwp032984/article/details/127571517