【每日日报】第三十五天

1 今天继续看书

打印流

package File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;

public class PrintStreamDemo {
    public static void main(String[] args)throws FileNotFoundException{
        PrintStream out=new PrintStream(new FileOutputStream("D:/Hello.txt"));
        out.println(true);
        out.println('A');
        out.println(10.0);
        out.println(12);
        out.println("Hello");
        Person p=new Person();
        p.setAge(20);
        p.setName("sky");
        out.println(p);
        out.close();
    }
}

使用RandomAccessFile随机读写文件

package File;
import java.io.IOException;
import java.io.RandomAccessFile;

public class RandomAccessFileDemo {
    public static void main(String[] args)throws IOException{
    RandomAccessFile acf = new RandomAccessFile("D:/Hello.txt","rw");
    byte[] b=("Hello Java!!").getBytes();
    acf.write(b);
    acf.seek(6);
    System.out.println("pointre="+acf.getFilePointer());
    byte[] b2="C++".getBytes();
    acf.write(b2);
    int len=-1;
    byte[] buf=new byte[1024];
    acf.seek(0);
    System.out.println("pointer="+acf.getFilePointer());
    while((len=acf.read(buf))!=-1){
        String s=new String(buf,0,len);
        System.out.println(s);
    }
  }
}

2  没遇到什么问题

3  明天继续看书写例题