JAVA读取文件方法大全

public static void readFileByBytes(String fileName) {
         File file = new File(fileName);
         InputStream in = null;
         try {
             System.out.println("以字节为单位读取文件内容，一次读一个字节：");
             // 一次读一个字节
             in = new FileInputStream(file);
             int tempbyte;
             while ((tempbyte = in.read()) != -1) {   
                 System.out.write(tempbyte);
             }
             in.close();   
         } catch (IOException e) {
             e.printStackTrace();
             return;
         }
         try {
             System.out.println("以字节为单位读取文件内容，一次读多个字节：");
             // 一次读100个字节
             byte[] tempbytes = new byte[100];
             int byteread = 0;
             in = new FileInputStream(fileName);