java - io

java中流的分类

1.按数据流的方法不同可以分为输入流和输出流
2.按处理数据单位的不同可以分为字节流和字符流
3.按功能的不同可以分为节点流和处理流
JDK所提供的所有流类型位于java.io内分别继承自一下四种抽象流类型

	字节流	字符流
输入流	InputStream	Reader
输出流	OutputStream	Writer

字节流

一个字节一个字节的读写
1.FileInputStream

FileInputStream in = null;
        int b =0;
        try {
            in = new FileInputStream("f:\\test.txt");
        } catch (FileNotFoundException e) {
            System.out.print("文件找不到");
            e.printStackTrace();
        }
        try {
            while ((b =in.read()) != -1){
                System.out.print((char)b);//这么转汉字（因为汉子是2个字节）会出错
            }
            in.close();
        } catch (IOException e) {
            System.out.println("文件读取错误");
            e.printStackTrace();
        }

2.FileOutputStream

        InputStream in = null;
        OutputStream out = null;
        try {
            in = new FileInputStream("f:\\test.txt");
            out = new FileOutputStream("f:\\copyTest.txt");
        } catch (FileNotFoundException e) {
            System.out.print("文件找不到");
            e.printStackTrace();
        }
        try {
            while ((b =in.read()) != -1){
                out.write(b);
            }
            in.close();
            out.close();
        } catch (IOException e) {
            System.out.println("文件复制完成");
            e.printStackTrace();
        }

字符流

一个字符一个字符的读写
1.FileReader

        Reader read = null;
        int b =0;
        try {
            read = new FileReader("f:\\test.txt");
        } catch (FileNotFoundException e) {
            System.out.print("文件找不到");
            
        }
        try {
            while ((b =read.read()) != -1){
                System.out.print((char)b);
            }
            read.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

2.FileWriter

               Reader read = null;
        Writer writer = null;
        int b = 0;
        try {
            read = new FileReader("f:\\test.txt");
            writer = new FileWriter("f:\\writerCopy");
        } catch (FileNotFoundException e) {
            System.out.print("文件找不到");
            
        }
        try {
            while ((b =read.read()) != -1){
                writer.write(b);
            }
            read.close();
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }