java高薪之路__005_IO流

参考地址：
1. http://blog.csdn.net/yczz/article/details/38761237

File类

ObjectInputStream  &&  ObjectOutputStream, 该流允许读取或写入用户自定义的类，但被读取或写入的类必须实现了Serializable接口 

DataInputStream  &&  DataOutputStream  有时没有必要存储整个对象的信息，而只是要存储一个对象的成员数据，成员数据的类型假设都是Java的基本数据类型，这样的需求不必使用到与Object输入、输出相关的流对象，可以使用DataInputStream、DataOutputStream来写入或读出数据
打算将Member类实例的成员数据写入文件中，并打算在读入文件数据后，将这些数据还原为Member对象。下面的代码简单示范了如何实现这个需求

 package com.hxw.io;  

 class Student implements Serializable{
    private String name;
    private int age;  

    public Student(String name, int age) {
       super();
       this.name = name;
       this.age = age;
    }  

    @Override
    public String toString() {
       return "Student [name=" + name + ", age=" + age + "]";
    }  

 }

 import java.io.*;
 public class ObjetStream {
    public static void main(String[] args) {
       ObjectOutputStream objectwriter = null;
       ObjectInputStream objectreader = null;  

       try {
          objectwriter = new ObjectOutputStream(new FileOutputStream("D:/David/Java/java 高级进阶/files/student.txt"));
          objectwriter.writeObject(new Student("gg", 22));
          objectwriter.writeObject(new Student("tt", 18));
          objectwriter.writeObject(new Student("rr", 17));  

          objectreader=new ObjectInputStream(new FileInputStream("D:/David/Java/java 高级进阶/files/student.txt"));
          for (int i = 0; i < 3; i++) {
             System.out.println(objectreader.readObject());
          }
       } catch (IOException | ClassNotFoundException e) {
          // TODO自动生成的 catch 块
          e.printStackTrace();
       }finally{
          try {
             objectreader.close();
             objectwriter.close();
          } catch (IOException e) {
             // TODO自动生成的 catch 块
             e.printStackTrace();
          }
       }
    }
 } 

 package com.hxw;
 public class Member {
     private String name;
     private int age;
     public Member() {
     }
    public Member(String name, int age) {
         this.name = name;
         this.age = age;
     }
     public void setName(String name){
         this.name = name;
     }
     public void setAge(int age) {
         this.age = age;
     }
     public String getName() {
         return name;
     }
     public int getAge() {
         return age;
     }
 }  

 import java.io.*;
 public class DataStreamDemo
 {
     public static void main(String[]args)
     {
         Member[] members = {new Member("Justin",90),
                 new Member("momor",95),
                 new Member("Bush",88)};
         try {
             DataOutputStream dataOutputStream = new DataOutputStream(new FileOutputStream(args[0]));  

             for(Member member:members)
             {
                 //写入UTF字符串
                 dataOutputStream.writeUTF(member.getName());
                 //写入int数据
                 dataOutputStream.writeInt(member.getAge());
             }  

             //所有数据至目的地
             dataOutputStream.flush();
             //关闭流
             dataOutputStream.close();  

             DataInputStream dataInputStream = new DataInputStream(new FileInputStream(args[0]));  

             //读出数据并还原为对象
             for(int i=0;i<members.length;i++)
             {
                 //读出UTF字符串
                 String name =dataInputStream.readUTF();
                 //读出int数据
                 int score =dataInputStream.readInt();
                 members[i] = new Member(name,score);
             }  

             //关闭流
             dataInputStream.close();  

             //显示还原后的数据
             for(Member member : members)
             {
                 System.out.printf("%s\t%d%n",member.getName(),member.getAge());
             }
         }
         catch(IOException e)
         {
             e.printStackTrace();
         }
     }
 }