Java学习记录(补充十:序列化以及异常处理)

Student类
package com.jredu.iodemo;

import java.io.Serializable;
import java.util.Date;

public class Student implements Serializable {   //序列化接口
    /**
     *序列化的版本ID 
     */
    private static final long serialVersionUID = 1L;
    private String stu_id;
    private String name;
    private Date birthday;
    public Student() {
        super();
    }
    public Student(String stu_id, String name, Date birthday) {
        super();
        this.stu_id = stu_id;
        this.name = name;
        this.birthday = birthday;
    }
    public String getStu_id() {
        return stu_id;
    }
    public void setStu_id(String stu_id) {
        this.stu_id = stu_id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    
}

序列化
package com.jredu.iodemo;

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.text.ParseException;
import java.text.SimpleDateFormat;

//序列化:把对象的状态存储到特定存储介质中的过程
//反序列化:从文件中读取对象的状态
//类通过实现 java.io.Serializable 接口以启用其序列化功能.
//未实现此接口的类将无法使其任何状态序列化或反序列化.


public class xuliehuaDemo {
    private static void xie(Student stu) {
        try {
            ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("G:/IO数据/stu.txt"));
            oos.writeObject(stu);
            oos.flush();
            oos.close();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    private static void du() {
        try {
            ObjectInputStream ois = new ObjectInputStream(new FileInputStream("G:/IO数据/stu.txt"));
            Object obj = ois.readObject();
            ois.close();
            if (obj!=null) {
                Student s1 = (Student)obj;
                System.out.println(s1.getName()+"	"+s1.getBirthday());
            }
            
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
    public static void main(String[] args) {
        Student stu = new Student();
        stu.setStu_id("170701");
        stu.setName("lizuowei");
        SimpleDateFormat sf = new SimpleDateFormat("yyyy/MM/dd");
        try {
            stu.setBirthday(sf.parse("1996/04/06"));
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        //写
        xie(stu);
        //读
        du();
    }

}

结果图:

     

序列化传递的是一个对象,不是二进制码,不能直接显示

message类
package com.jredu.iodemo;

public class MyException extends RuntimeException {
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private String message;

    public MyException() {
        super();
    }

    public MyException(String message) {
        super();
        this.message = message;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }
    
    
}

异常处理
package com.jredu.iodemo;
//throw throws
public class TestException2 {
    public void throwMyException() throws MyException {
        System.out.println("我要抛异常了...");
        throw new MyException("我自定义的异常");

    }

    public static void main(String[] args) {
        TestException2 t2 = new TestException2();
        try {
            t2.throwMyException();
        } catch (MyException e) {
            System.out.println("我来处理");
            System.out.println(e.getMessage());
            //e.printStackTrace();
            MyLog.log(e.getMessage()+" "+t2.getClass().toString());
        }
    }
}

return关键字和finally

package com.jredu.iodemo;
//有return时
public class TestException3 {
    public  int test(){
        int n=10;    //10    
        try{
            n++;    //11
            int m=9/0;//异常
            n++;
            return n;
        }catch(Exception e){
            n=n+1;    //12
            return n;
            
        }finally{
            n=30;
            System.out.println("finally");    
        }
        
        
    }
    public static void main(String[] args) {
        TestException3 result = new TestException3();
        System.out.println(result.test());
    }

}

结果图: