IO流的基本概念

1.基类
InputStream,OutputStream.都是接口.
2.流的分类
a.处理
  字节流和字符流
字节流由InputStream和OutputStream处理，而字符流由Reader和Writer处理。
b.输入和输出
3.流的基本创建方法
InputStream inputStream = new FileInputStream(String filepath);
OutputStream outputSteam = new FileOutputStream(String filepath);

File 有3中创建对象的方法
  File file = new File(String filepath);
  File file = new File(File file,String fileName);
  File file = new File(String filepath,String fileName);
4.最常用的方法
read--完成返回值-1,write,flash.
5.实例

InputStream inputs =null;
		OutputStream output =null;
		try {
			inputs = new FileInputStream(fromFile);
			output = new FileOutputStream(tofile);
			byte[] b = new byte[1024];
			int len = inputs.read(b);
			while(len!=-1){
				output.write(b, 0, len);
				len = inputs.read(b);
			}
			//System.out.println("----------copy successful-------------");
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}finally{
			if(inputs!=null){
				try {
					inputs.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if(output!=null){
				try {
					output.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}