寫文字資料

方法 一：

import java.io.*;

public class A {

    public static void main(String args[]) {
        FileOutputStream out;
        PrintStream ps;
        try {
            out = new FileOutputStream("a.txt");
            ps = new PrintStream(out);
            ps.println("qun qun.");
            ps.println("fei fei");
            ps.close();
        } catch (Exception e) {
            System.out.println(e.toString());
        }
    }
}

方法 二：

import java.io.*;

public class B {

    public static void main(String args[]) {
        FileWriter fw;
        PrintWriter pw;
        try {
            fw = new FileWriter("b.txt");
            pw = new PrintWriter(fw);
            pw.print("qunqu n ");
            pw.println("feiefi ss");
            pw.print("qunqu n ");
            pw.close();
            fw.close();
        } catch (IOException e) {
            System.out.println(e.toString());
        }
    }
}

方法三：

import java.io.*;

public class C {

    public static void main(String args[]) {
        String str_written = "This is a simple example";
        try {
            FileWriter fwriter = new FileWriter("c.txt");
            BufferedWriter bfwriter = new BufferedWriter(fwriter);
            bfwriter.write(str_written, 0, str_written.length());
            bfwriter.flush();
            bfwriter.close();
        } catch (IOException e) {
            System.out.println(e.toString());
        }
    }
}
附註：方法一和方法二，方法三都是在操作文字檔案不存在的時候將建立，否則，當覆蓋之！

令；方法三

BufferedWriter將文字寫入字元輸出流，緩衝各個字元，從而提供單個字元、陣列和字串的高效寫入。

附：追加寫入：

import java.io.*;

public class C {

    public static void main(String args[]) {
        String str_written = "This is a simple example";
        try {
            FileWriter fwriter = new FileWriter("c.txt", true);
            BufferedWriter bfwriter = new BufferedWriter(fwriter);
            bfwriter.newLine();
            bfwriter.write(str_written, 0, str_written.length());
            bfwriter.flush();
            bfwriter.close();
        } catch (IOException e) {
            System.out.println(e.toString());
        }
    }
}

讀文字資料

方法一：

import java.io.*;

public class A {

    public static void main(String args[]) {
        try {
            FileInputStream fstream = new FileInputStream("a.txt");
            DataInputStream in = new DataInputStream(fstream);
            while (in.available() != 0) {
                String a = in.readLine();
                System.out.println(a);
                System.out.println(a.length());
            }
            in.close();
        } catch (Exception e) {
            System.out.println(e.toString());
        }
    }
}

方法二：

import java.io.*;

public class B {

    public static void main(String args[]) {
        try {
            FileReader fr = new FileReader("a.txt");
            BufferedReader br = new BufferedReader(fr);
            String str;
            int count = 0;
            while ((str = br.readLine()) != null) {
                count++;
                System.out.println(count + " : " + str);
            }
            br.close();
            fr.close();
        } catch (Exception e) {
            System.out.println(e.toString());
        }
    }
}

附：方法二的能夠高效的實現文字資料的讀出