HttpURLConnection根据URL下载图片

来看下最简单的根据URL下载图片，此方法在实际开发中，不建议使用，因为有些图片是下载不了的，比如百度上的一些图片，返回http的响应码是405

[java] view plaincopy

1. package cn.ztz.test;  
2.   
3. import java.io.BufferedOutputStream;  
4. import java.io.File;  
5. import java.io.FileOutputStream;  
6. import java.io.InputStream;  
7. import java.io.OutputStream;  
8. import java.net.HttpURLConnection;  
9. import java.net.InetAddress;  
10. import java.net.URL;  
11.   
12. public class HttpDownLoad {  
13.     public static void download(String url, String dir,String fileName) {  
14.         HttpURLConnection httpURLConnection = null;  
15.         OutputStream out = null;  
16.         InputStream in = null;  
17.         try {  
18.             URL sendUrl = new URL(url);  
19.             httpURLConnection = (HttpURLConnection) sendUrl.openConnection();  
20.             httpURLConnection.setRequestMethod("POST");  
21.             httpURLConnection.setRequestProperty("contentType", "utf-8");  
22.             httpURLConnection.setDoOutput(true);   
23.             httpURLConnection.setUseCaches(false);  
24.             httpURLConnection.setConnectTimeout(3000);  
25.             httpURLConnection.setReadTimeout(3000);  
26.             httpURLConnection.setRequestProperty(  
27.                     "User-agent",InetAddress.getLocalHost().getHostAddress() + ":"  
28.                             + System.getProperty("catalina.home"));  
29.             out = httpURLConnection.getOutputStream();  
30.             // 清空缓冲区数据  
31.             out.flush();  
32.             // 获取HTTP状态码  
33.             int httpStatusCode = httpURLConnection.getResponseCode();  
34.             if(httpStatusCode!=200){  
35.                 throw new RuntimeException("异常");  
36.             }  
37.             in = httpURLConnection.getInputStream();  
38.             // 获取文件长度  
39.             int len = httpURLConnection.getContentLength();  
40.             // 路径+文件名  
41.             String pathAndName = dir + File.separator + fileName;  
42.             // 保存文件  
43.             saveFileByByte(in, pathAndName, len);  
44.         } catch (Exception e) {  
45.             e.printStackTrace();  
46.         } finally {  
47.             if (out != null) {  
48.                 try {  
49.                     out.close();  
50.                 } catch (Exception e) {  
51.                     e.printStackTrace();  
52.                     throw new RuntimeException(e.getMessage());  
53.                 }  
54.             }  
55.             if (in != null) {  
56.                 try {  
57.                     in.close();  
58.                 } catch (Exception e) {  
59.                     e.printStackTrace();  
60.                 }  
61.             }  
62.             if (httpURLConnection != null) {  
63.                 httpURLConnection.disconnect();  
64.                 httpURLConnection = null;  
65.             }  
66.         }  
67.     }  
68.   
69.     //写文件  
70.     private static void saveFileByByte(InputStream in, String path, int len)  
71.             throws Exception {  
72.         byte[] byteDatas = new byte[len];  
73.         BufferedOutputStream bw = null;  
74.         try {  
75.             // 创建文件对象  
76.             File f = new File(path);  
77.             // 创建文件路径  
78.             if (!f.getParentFile().exists())  
79.                 f.getParentFile().mkdirs();  
80.             // 写入文件  
81.             bw = new BufferedOutputStream(new FileOutputStream(path));  
82.             int bytesRead = 0;  
83.             while ((bytesRead = in.read(byteDatas, 0, byteDatas.length)) != -1) {  
84.                 bw.write(byteDatas, 0, bytesRead);  
85.             }  
86.         } catch (Exception e) {  
87.             e.printStackTrace();  
88.             throw e;  
89.         } finally {  
90.             try {  
91.                 if (bw != null)  
92.                     bw.close();  
93.             } catch (Exception e) {  
94.                 throw e;  
95.             }  
96.         }  
97.     }  
98. }