java-打印流和Scanner使用用例，序列化反序列化用例

在桌面上新建一个Test.txt,使用打印流向文件中输出如下: 
Hello 123 

hello World

package com.PrinIO;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

public class Test {
	public static void main(String[] args) throws IOException, InterruptedException   {
		File file = new File("C:\\Users\\Administrator\\Desktop\\test.txt");
		if(!file.exists()) {
			file.createNewFile();
		}
		PrintWriter pw = new PrintWriter(file);
		pw.write("Hello 123\r\n");
		pw.write("Hello World\r\n");
		pw.close();		//一个小坑，若不关闭该打印流，则下列Scanner将无法读入
		
		Scanner scanner = new Scanner(new FileInputStream(file));
		scanner.useDelimiter("\r\n");
		while(scanner.hasNext()) {
			System.out.println(scanner.next());
		}
		scanner.close();
	}
}

自定义Person类，其中三个属性name,age,school. 

age属性不作为序列化保存而其他两个属性使用序列化保存在本地文件TestSer.txt中

package com.PrinIO;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;	//注意添加包

@SuppressWarnings("serial")
class Person implements Serializable{
	private String name;
	private transient Integer age;    //使用transient修饰将不会被序列化到文本当中
	private String school;
	public Person(String name, Integer age, String school) {
		super();
		this.name = name;
		this.age = age;
		this.school = school;
	}
	@Override
	public String toString() {
		return "Person [name=" + name + ", age=" + age + ", school=" + school + "]";
	}
}

public class Test2 {
	public static void main(String[] args) throws FileNotFoundException, IOException, ClassNotFoundException {
		Person person = new Person("张三", 20, "蓝翔技校");
		File file = new File("C:\\Users\\Administrator\\Desktop\\person.txt");
		if(!file.exists()) {
			file.createNewFile();
		}
		ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(file));
		oos.writeObject(person);
		oos.close();
		ObjectInputStream ois = new ObjectInputStream(new FileInputStream(file));
		Object tmp = ois.readObject();
		ois.close();
		System.out.println(tmp);
	}
}

一道算法: 

    输入一个5位数，判断它是不是回文数。即12321是回文数，个位与万位相同，十位与千位相同。

public class Test3 {
	public static void main(String[] args) {
		System.out.println("是否是回文数？"+isHuiWen(123454321));
	}
	//  输入一个5位数，判断它是不是回文数。即12321是回文数，个位与万位相同，十位与千位相同。 加强，输入任意长度的数：123454321
	public static boolean isHuiWen(int num) {
		int tmp=num, len=1;
		while(tmp>=10) {
			tmp/=10;
			len++;
		}
		len = len/2;
		for(int i=0;i<len;i++) {
			int left = (num/(tenN(len*2-i)))%10;
			int right = num/(tenN(i))%10;
			System.out.println("left:"+left+",right"+right);
			if(left!=right) {
				return false;
			}
		}
		return true;
	}
	public static int tenN(int n) {
		int a = 1;
		for(int i=0;i<n;i++) {
			a*=10;
		}
		return a;
	}
}