java 网络文件大小_Java 读取网络资源文件 获取文件大小 MD5校验值

Java 读取网络资源文件 获取文件大小 MD5校验值

封装一个文件操作工具类：

package c;

import java.io.*;

import java.net.HttpURLConnection;

import java.net.MalformedURLException;

import java.net.URL;

/**

* @author Jayvee

* @Description: todo 文件操作

*/

public class FileUtils {

/**

* @author Jayvee

* @Description: todo 获取网络文件的大小

*/

public static int getFileLength(String url1) throws IOException {

int length = 0;

URL url;

try {

url = new URL(url1);

HttpURLConnection urlcon = (HttpURLConnection) url.openConnection();

//根据响应获取文件大小

length = urlcon.getContentLength();

urlcon.disconnect();

} catch (MalformedURLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return length;

}

/**

* 从输入流中获取字节数组

* @author Jayvee

* @param inputStream

* @return

* @throws IOException

*/

public static byte[] readInputStream(InputStream inputStream) throws IOException {

byte[] buffer = new byte[1024];

int len = 0;

ByteArrayOutputStream bos = new ByteArrayOutputStream();

while ((len = inputStream.read(buffer)) != -1) {

bos.write(buffer, 0, len);

}

bos.close();

return bos.toByteArray();

}

/**

* @author Jayvee

* @Description: todo

*/

public static byte[] downLoadFromUrl(String urlStr) throws IOException {

URL url = new URL(urlStr);

HttpURLConnection conn = (HttpURLConnection) url.openConnection();

InputStream inputStream = conn.getInputStream();

//获取自己数组

byte[] getData = readInputStream(inputStream);

return getData;

}

/**

* @author Jayvee

* @Description: todo

*/

public static byte[] readFromByteFile(String pathname) throws IOException {

File filename = new File(pathname);

BufferedInputStream in = new BufferedInputStream(new FileInputStream(filename));

ByteArrayOutputStream out = new ByteArrayOutputStream(1024);

byte[] temp = new byte[1024];

int size = 0;

while ((size = in.read(temp)) != -1) {

out.write(temp, 0, size);

}

in.close();

byte[] content = out.toByteArray();

return content;

}

}

try {

int fileSize = FileUtils.getFileLength("http://pic.962.net/up/2018-1/2018191570320420.jpg"); // 获取文件大小

byte[] file = FileUtils.downLoadFromUrl("http://pic.962.net/up/2018-1/2018191570320420.jpg"); // 获取文件内容

System.out.println("文件大小：" + fileSize + " 字节");

System.out.println("文件内容：" + file);

} catch (IOException e) {

e.printStackTrace();

}

执行结果：

文件大小：4979 字节

文件内容：[B@7dc5e7b4

获取网络文件的md5校验值：

try {

byte[] file = FileUtils.downLoadFromUrl("http://pic.962.net/up/2018-1/2018191570320420.jpg"); // 获取文件内容

System.out.println(DigestUtils.md5DigestAsHex(file)); // 文件内容md5校验

} catch (IOException e) {

e.printStackTrace();

}

执行结果：

cc2fdb7b2366a086f30e5af3c63b230c