字符缓冲流

package FileT.Day4;
/**
 * @author CCQ
 * 字符缓冲流复制文件。
 */

import java.io.*;

public class BufferedRWTest {
    public static void main(String[] args) throws IOException {
        BufferedReader br =new BufferedReader(new FileReader("fox.txt"));
        BufferedWriter bw =new BufferedWriter(new FileWriter("fff.txt"));
        char[] chars =new char[1024];
        int len;
        while ((len =br.read(chars))!=-1){
            System.out.println(new String(chars,0,len));
            bw.write(chars,0,len);
        }
        br.close();
        bw.close();
    }
}

package FileT.Day4;
/**
 * @author CCQ
 * 字符缓冲流的两个特有方法
 * Read：
 *  String	readLine()
 *      读取一行数据，但不会读换行符。读到最后没有数据可读的时候会返回null值
 *
 * Write：
 *  void  newLine()
 *      写入一个换行符。
 */

import java.io.*;

public class BufferedRWTest2 {
    public static void main(String[] args) throws IOException {
        BufferedReader br =new BufferedReader(new FileReader("fox.txt"));
        BufferedWriter bw =new BufferedWriter(new FileWriter("fff.txt"));
        String line;
        while ((line =br.readLine())!=null){
            System.out.println(line);
            bw.write(line);
            bw.newLine();
        }

//        for (int i = 0; i < 10; i++) {
//            bw.write("你好啊。");
//            bw.newLine();
//        }


        br.close();
        bw.close();
    }
}

---

几个小demo：

package FileT.Day4;

import java.io.*;
import java.util.ArrayList;
import java.util.Iterator;

/**
 * @author CCQ
 * 将集合元素写入到文件
 */
public class demo {
    public static void main(String[] args) throws IOException {
        ArrayList<String> al =new ArrayList<>();
        al.add("hello");
        al.add("world");
        al.add("java");
        BufferedWriter bw =new BufferedWriter(new FileWriter("fox.txt"));
        Iterator<String> iterator = al.iterator();
        while (iterator.hasNext()){
            bw.write(iterator.next());
            bw.newLine();
        }
        bw.close();
    }
}

/**
 *
 * @author CCQ
 * 将文件的一行作为一个元素写入集合
 */
class demo1{
    public static void main(String[] args) throws IOException{
        BufferedReader br =new BufferedReader(new FileReader("fox.txt"));
        ArrayList<String> al =new ArrayList<>();
        String s;
        while ((s =br.readLine())!=null){
            al.add(s);
        }
        Iterator<String> iterator = al.iterator();
        while (iterator.hasNext()){
            System.out.println(iterator.next());
        }
        br.close();
    }
}

package FileT.Day4;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Random;

/**
 * @author CCQ
 * 点名器
 */
public class DMQ {
    public static void main(String[] args) throws IOException {
        BufferedReader br =new BufferedReader(new FileReader("fox.txt"));
        ArrayList<String> al =new ArrayList<>();
        String s;
        while ((s =br.readLine())!=null){
            al.add(s);
        }
        Iterator<String> iterator = al.iterator();
        while (iterator.hasNext()){
            System.out.println(iterator.next());
        }
        br.close();
        Random r =new Random();
        int index =r.nextInt(al.size());
        System.out.println(al.get(index));
    }
}