目錄

8. BufferedReader/BufferedWriter
   --8.1 BufferedReader 緩沖輸入字符流
   --8.2 BufferedWriter 緩存輸出字符流
   --8.3 用BufferedWriter和BufferedReader進(jìn)行拷貝

8. BufferedReader/BufferedWriter(需要flush()才可寫(xiě)入)

8.1 BufferedReader

讀取字符時(shí)會(huì)一次讀取若干字符到緩沖區(qū)，然后逐個(gè)返回給程序，降低讀取文件的次數(shù)。

1. BufferedReader常用構(gòu)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

寫(xiě)出字符時(shí)先寫(xiě)到緩沖區(qū)，緩沖區(qū)寫(xiě)滿再寫(xiě)到文件，降低寫(xiě)文件的次數(shù)，提高效率。

1. BufferedWriter常用構(gòu)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() //可輸入一個(gè)跨平臺(tái)的換行符
public void flush() 
public void close()

8.3 用BufferedWriter和BufferedReader進(jìn)行拷貝

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();//可輸入一個(gè)跨平臺(tái)的換行符
            bw.flush();
        }

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