javaIO流2

JavaIO流2

缓冲流

提高读、写效率

原因：内部提供缓冲区

BufferedInputStream BufferedOutputStream 的使用

在 FileInputStream和 FileOutputStream的基础上微微改动

            复制非文本文件
            //造流
            FileInputStream fis = new FileInputStream(comefile);
            FileOutputStream fos = new FileOutputStream(gofile);

            //造缓冲流
            bis = new BufferedInputStream(fis);
            bos = new BufferedOutputStream(fos);
            
            byte[] buffer = new byte[10];
            int len = bis.read(buffer);
            while (len != -1){
                bos.write(buffer,0,len);
            }
//bos.flush:清空缓冲区

BufferedReader BufferedWriter 的使用

//复制文本文件
BufferedReader br = new BufferedReader(new FileReader(new File("文件名1")));
BufferedWriter bw = new BufferedWriter(new FileWriter(new File("文件名2"))) 
   //方式一：只用char[]数组
            char[]cbuf = new char[1024];
            int len = br.read(cbuf);
            while (len != -1){
                bw.write(cbuf,0,len);
                bw.flush
            }
   //方式二：使用String
             String date  = br.readLine();//一行一行的读取
             while(date != null){
                 bw.write(date+"\n")//输出一行date里不包括换行符
                或是： bw.newline;
                 date  = br.readLine();    
             }            

转换流

字符流，字节流之间的转换

InputStreamRrader:将一个字节的输入流转化为字符的输入流

OutputStreamWriter:将一个字符的输出流转化为字节的输出流

 InputStreamReader isr = null;
        OutputStreamWriter osr = null;
        try {
            File comefile = new File("src\\hello");
            File gofile = new File("src\\hello_gbk");

            FileInputStream fis = new FileInputStream(comefile);
            FileOutputStream fos = new FileOutputStream(gofile);

            isr = new InputStreamReader(fis);//解码
            osr = new OutputStreamWriter(fos,"gbk");//编码

            char[] cubf = new char[20];
            int len;
            while((len = isr.read(cubf)) != -1){
                osr.write(cubf,0,len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
        }
        try {
            if(osr != null)
                osr.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        try {
            if(isr != null)
                isr.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

字符集

将x拼在一起就是二进制了