目录

8. BufferedReader/BufferedWriter
   --8.1 BufferedReader 缓冲输入字符流
   --8.2 BufferedWriter 缓存输出字符流
   --8.3 用BufferedWriter和BufferedReader进行拷贝

8. BufferedReader/BufferedWriter(需要flush()才可写入)

8.1 BufferedReader

读取字符时会一次读取若干字符到缓冲区，然后逐个返回给程序，降低读取文件的次数。

1. BufferedReader常用构造方法

public BufferedReader(Reader in)

2. BufferedReader重要方法

public int read()
public int read(char cbuf[], int off, int len)
String readLine(boolean ignoreLF)
public String readLine()

8.2 BufferedWriter

写出字符时先写到缓冲区，缓冲区写满再写到文件，降低写文件的次数，提高效率。

1. BufferedWriter常用构造方法

public BufferedWriter(Writer out)

2. BufferedWriter重要方法

public void write(int c) 
public void write(char cbuf[], int off, int len)
public void write(String s, int off, int len)
public void newLine() //可输入一个跨平台的换行符
public void flush() 
public void close()

8.3 用BufferedWriter和BufferedReader进行拷贝

方式一：

        File dir = Environment.getExternalStorageDirectory();
        File file = new File(dir, "abc.txt");
        File dst = new File(dir, "dst4.txt");

        FileReader fr = new FileReader(file);
        BufferedReader br = new BufferedReader(fr);
        FileWriter fw = new FileWriter(dst);
        BufferedWriter bw = new BufferedWriter(fw);


        int len = -1;
        char[] buffer = new char[1024];
        while ((len = br.read(buffer)) != -1) {
            bw.write(buffer, 0, len);
            bw.flush();
        }

        fr.close();
        br.close();
        fw.close();
        fw.close();

方式二：

        File dir = Environment.getExternalStorageDirectory();
        File file = new File(dir, "abc.txt");
        File dst = new File(dir, "dst4.txt");

        FileReader fr = new FileReader(file);
        BufferedReader br = new BufferedReader(fr);
        FileWriter fw = new FileWriter(dst);
        BufferedWriter bw = new BufferedWriter(fw);


        String line = null;
        while((line = br.readLine())!=null){
            bw.write(line);
            bw.newLine();//可输入一个跨平台的换行符
            bw.flush();
        }

        fr.close();
        br.close();
        fw.close();
        fw.close();