其他流

ObjectInput/OutputStream

分别与FileOutputStream和FileInputStream一起使用时,可以为应用程序提供对对象的持久存储.

我们把对象以某种特定的编码格式写入称之为"序列化"

把写入的编码格式内容还原成对象称之为"反序列化"

被序列化的对象必须实现Serializable接口

　　  

package otherio;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

public class ObjectInputOutputDemo {
     public static void main(String[] args) throws IOException {
    /*    Student student=new Student("张三", 20);
        FileOutputStream fos=new FileOutputStream(new File("D:\a.txt"));
        ObjectOutputStream os=new ObjectOutputStream(fos);
        ObjectOutputStream os=new ObjectOutputStream(new FileOutputStream(new File("D:\a.txt")));
        os.writeObject(student);//把对象序列化到指定的文件输出流中
        os.close();*/
         
        ObjectInputStream ois=new ObjectInputStream(new FileInputStream(new File("D:\\a.txt")));
        try {
            Student student=(Student) ois.readObject();
            System.out.println(student.getName()+" "+student.getAge());
        } catch (ClassNotFoundException e) {
            
            e.printStackTrace();
        }
    
        
    }
}

class Student implements Serializable{

    
    /**
     * 
     */
    private static final long serialVersionUID = 3655643694434659371L;
    private String name;
    private int age;
    private String address;
    
    
    public Student(String name, int age) {
    
        this.name = name;
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    
}

InputStreamReader/OutputStreamWriter

　　转换流  指将字节流与字符流之间的转换

package otherio;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;


public class InputStreamReaderWriterDemo {
  public static void main(String[] args) throws IOException {
      /*OutputStreamWriter w=new OutputStreamWriter(new FileOutputStream(new File("D:\aa.txt")), "utf-8");
      BufferedWriter bw=new BufferedWriter(w);
      bw.write("你好");
      bw.close();*/
      
      BufferedReader bReader=new BufferedReader(new InputStreamReader(
              new FileInputStream(new File("D:\aa.txt")), "utf-8"));
      String line =null;
      while((line=bReader.readLine())!=null) {
        System.out.println(line);          
       }
      bReader.close();
  }
}

RandomAccessFile

　　随机访问文件

package otherio;

import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.Scanner;

public class RandomAccessFileDemo {
public static void main(String[] args) throws IOException {
    Person[] persons= {new Person("zhangs",90),new Person("justin",30),new Person("bush",88),new Person("lisi",20)};
    RandomAccessFile reFile= new RandomAccessFile("D:\a.txt", "rw");
    //写入数据到RandomAccessFile中
    for (int i = 0; i < persons.length; i++) {
        reFile.writeChars(persons[i].getName());
        reFile.writeChar(persons[i].getAge());
    }
    
    //读取指定位置的person对象
    Scanner scanner=new Scanner(System.in);
    System.out.println("读取第几个oerson对象数据");
    int  num=scanner.nextInt();
    //使用seek方法来操作存取位置
    reFile.seek((num-1)*Person.size());
    Person person=new Person();
    person.setName(readName(reFile));
    person.setAge(reFile.readInt());
    System.out.println(person.getName()+person.getAge());
    reFile.close();
}
        private static String  readName(RandomAccessFile randomAccessFile) throws IOException {
            char[] name=new char[15];
            for (int i = 0; i < name.length; i++) {
                name[i]=randomAccessFile.readChar();
            }
            return new String(name).replace('u0000', ' ');
        }
}

class Person {
    private String name;
    private int age;

    public Person() {
        super();
    }

    public Person(String name, int age) {
        StringBuilder builder = null;
        if (name != null) {
            builder = new StringBuilder(name);
        } else {
            builder = new StringBuilder(15);
        }
        builder.setLength(15);// 固定长度为15个,占了30个字节的大小,后面以空字符'u0000'
        this.name = builder.toString();
        this.age = age;

    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        StringBuilder builder = null;
        if (name != null) {
            builder = new StringBuilder(name);
        } else {
            builder = new StringBuilder(15);
        }
        builder.setLength(15);// 固定长度为15个,占了30个字节的大小,后面以空字符'u0000'
        this.name = builder.toString();
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    // 每个对象所占的字节数
    public static int size() {
        return 34;
    }

}