爪哇国新游记之三十三----目录文件操作

1.判断路径是文件还是目录

File subDir=new File("c:\mp3");
if(subDir.isDirectory()){
   // 是目录
}

File mp3=new File("c:\mp3\avemaria.mp3");
                    
if(mp3.isFile()){
   // 是文件
}

2.列出目录下的文件和子目录

File dir = new File(fromDir);
String[] children = dir.list();

for (int i=0; i<children.length; i++) {
    String filename = children[i];
    ...
}

3.文件拷贝

public static void copyFile(File sourceFile, File targetFile) throws IOException {
        BufferedInputStream inBuff = null;
        BufferedOutputStream outBuff = null;
        try {
            // 新建文件输入流并对它进行缓冲
            inBuff = new BufferedInputStream(new FileInputStream(sourceFile));

            // 新建文件输出流并对它进行缓冲
            outBuff = new BufferedOutputStream(new FileOutputStream(targetFile));

            // 缓冲数组
            byte[] b = new byte[1024 * 5];
            int len;
            while ((len = inBuff.read(b)) != -1) {
                outBuff.write(b, 0, len);
            }
            // 刷新此缓冲的输出流
            outBuff.flush();
        } finally {
            // 关闭流
            if (inBuff != null)
                inBuff.close();
            if (outBuff != null)
                outBuff.close();
        }
    }

2016年8月26日23:39:27改版

/**
     * 将文件上传到服务器，返回在服务器的路径文件名
     * @param in
     * @param filename
     * @return
     * @throws Exception
     */
    public String upload2Server(InputStream in, String filename) throws Exception {
        BufferedInputStream inBuff = null;
        BufferedOutputStream outBuff = null;
        try {
            // 新建文件输入流并对它进行缓冲
            inBuff = new BufferedInputStream(in);

            // 新建文件输出流并对它进行缓冲
            String filePathname=uploadPath+getTimePrefix()+filename;
            outBuff = new BufferedOutputStream(new FileOutputStream(new File(filePathname)));

            // 缓冲数组
            byte[] b = new byte[1024 * 5];
            int len;
            while ((len = inBuff.read(b)) != -1) {
                outBuff.write(b, 0, len);
            }
            // 刷新此缓冲的输出流
            outBuff.flush();
            
            return filePathname;
        } catch(Exception ex){
            logger.error(ex);
            throw ex;
        }
        finally {
            // 关闭流
            if (inBuff != null)
                inBuff.close();
            if (outBuff != null)
                outBuff.close();
        }
    }

4.取得操作系统的临时目录

String folder=System.getProperty("java.io.tmpdir");