public static void main(String[] args) throws FileNotFoundException,
            IOException {
        // 建立File对象
        File srcFile = new File("");
        // 选择流
        InputStream isInputStream = null;// 提升作用域
        try {
            isInputStream = new FileInputStream(srcFile);
            // 操作不断读取缓冲数组
            byte[] car = new byte[10];
            int len = 0;// 接收实际读取大小
            // 循环读取
            while (-1 != isInputStream.read(car)) {
                // 输出字节数组转成字符串
                String info = new String(car, 0, len);
                System.err.println(info);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            System.out.println("文件不存在");
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("读取文件失败");
        } finally {
            try {
                if (null != isInputStream) {
                    isInputStream.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
                System.out.println("关闭文件输入流失败");
            }
        }

    }

public static void main(String[] args) throws FileNotFoundException,
            IOException {
        // 建立File对象目的地
        File dest = new File("");
        // 选择流,文件输出流OutputStream   FileOutputStream
        OutputStream out = null;// 提升作用域
        try {
            //true以追加的形式写出文件，否则是覆盖
            out = new FileOutputStream(dest,true);
            String str="abcdedg"; 
            //字符串转字节数组
            byte[] data=http://www.mamicode.com/str.getBytes();
            out.write(data,0,data.length);
                
            out.flush();//强制刷新出去
            
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            System.out.println("文件未找到");
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("写出文件失败");
        } finally {
            try {
                //释放资源：关闭
                if (null != out) {
                    out.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
                System.out.println("关闭文件输出流失败");
            }
        }

    }