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〖第12章：JAVA IO〗_实例操作—单人信息管理程序

发布时间：2020-12-31 16:52:25编辑：雪饮阅读（）

 基于对象序列化完成一个单人信息管理程序

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.File;
import java.io.Serializable;
import java.io.FileWriter;
import java.io.ObjectInputStream;
import java.io.InputStream;
import java.io.FileInputStream;
import java.io.OutputStream;
import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.io.FileNotFoundException;
import java.io.EOFException;
class Menu{
       private Operate operate=new Operate();
       public Menu(){
              this.show();
       }
       public void show(){
              System.out.println("[0]初始化");
              System.out.println("[1]增加数据");
              System.out.println("[2]删除数据");
              System.out.println("[3]修改数据");
              System.out.println("[4]查看数据");
              System.out.println("[5]退出系统");
              try{
                     int select_index=new InputData().getInt("请选择操作:","只能输入数字!");
                     if(select_index==0){
                            operate.init();
                     }
                     if(select_index==1){
                            operate.add();
                     }
                     if(select_index==2){
                            operate.delete();
                     }
                     if(select_index==3){
                            operate.update();
                     }
                     if(select_index==4){
                            operate.find();
                     }
                     if(select_index==5){
                            System.exit(0);
                     }
              }
              catch(NullPointerException e){
                     //监听用户ctrl+c
                     System.exit(0);
              }
              catch(Exception e){
                     e.printStackTrace() ;
              }
             
       }
}
class Person implements Serializable{
       private static final long serialVersionUID=1L;
       private String name;
       private int age;
       public Person(String name,int age){
              this.name=name;
              this.age=age;
       }
       public String toString(){
              return "姓名:"+this.name+",年龄:"+this.age;
       }
}
class Operate{
       private File file=new File("d:"+File.separator+"kasumis.txt");
       public void init(){
              try {
                     if(!this.file.exists())   
                     {
                            this.file.createNewFile();              
                     }
                     else{
                            FileWriter fileWriter =new FileWriter(this.file);
                            fileWriter.write("");
                            fileWriter.flush();
                            fileWriter.close();
                     }
                     System.out.println("初始化完成");
                     new Menu();
              }
              catch(IOException e){
                     e.printStackTrace(); 
              }           
       }
       public Object[] getSerializeables(){
              Object obj[]=null;
              try{
                     InputStream input = new FileInputStream(this.file) ;
                     ObjectInputStream ois = new ObjectInputStream(input) ;
                     obj = (Object[])ois.readObject() ;
                     ois.close() ;
                    
              }
              catch(EOFException e){
                     //空文件没有任何序列化对象时会报该异常EOFException
                     obj=new Object[0];
              }
              catch(FileNotFoundException e){
                     e.printStackTrace() ;
              }
              catch(IOException e){
                     e.printStackTrace() ;
              }
              catch(ClassNotFoundException e){
                     e.printStackTrace() ;
              }
              return obj;
       }
       public void ser(Object obj[]) throws Exception {
              OutputStream out = new FileOutputStream(this.file) ;
              ObjectOutputStream oos = new ObjectOutputStream(out) ;
              oos.writeObject(obj) ;
              oos.close() ;
       }
       public void add() throws Exception{
              String name=new InputData().getString("请输入姓名:");
              int age=new InputData().getInt("请输入年龄:","只能输入数字!");
             
              Object oldData[]=getSerializeables();
              int slen=oldData.length;
             
              Person pers[]= new Person[slen+1];
              for(int i=0;i<slen;i++){
                     pers[i]=(Person)oldData[i];
              }
             
              pers[slen]=new Person(name,age);
              this.ser(pers);
              System.out.println("增加成功");
              new Menu();
       }
       public void delete() throws Exception{
              Object obj[]=getSerializeables();
              if(obj.length==0){
                     System.out.println("暂无任何数据!");
              }
              else{
                     for(int i=0;i<obj.length;i++){
                            System.out.println("["+i+"]:"+obj[i]);
                     }
                     int select_index=new InputData().getInt("请输入要删除的数据下标:","只能输入数字!");
                     Object newObj[]=new Object[obj.length-1];
                     int temp=0;
                     for(int i=0;i<obj.length;i++){
                            if(i!=select_index){
                                   newObj[temp]=obj[i];
                            }
                            temp++;
                     }
                     this.ser(newObj);
                     System.out.println("删除成功");
              }
              new Menu();
       }
       public void update() throws Exception{
              Object obj[]=getSerializeables();
              if(obj.length==0){
                     System.out.println("暂无任何数据!");
              }
              else{
                     for(int i=0;i<obj.length;i++){
                            System.out.println("["+i+"]:"+obj[i]);
                     }
                     int select_index=new InputData().getInt("请输入要修改的数据下标:","只能输入数字!");
                     String name=new InputData().getString("请输入姓名:");
                     int age=new InputData().getInt("请输入年龄:","只能输入数字!");
                     Object person=new Person(name,age);
                     for(int i=0;i<obj.length;i++){
                            if(i==select_index){
                                   obj[i]=person;
                            }
                     }
                     this.ser(obj);
                     System.out.println("修改成功");
              }
              new Menu();
       }
       public void find(){
              Object obj[]=getSerializeables();
              if(obj.length==0){
                     System.out.println("暂无任何数据!");
              }
              else{
                     for(int i=0;i<obj.length;i++){
                            System.out.println("["+i+"]:"+obj[i]);
                     }
              }
              String q=new InputData().getString("输入‘q’键回首页:");
              if(q.equals("q")){
                     new Menu();
              }
       }
};
class InputData{
       private BufferedReader buf = new BufferedReader(new InputStreamReader(System.in));
       public String getString(String info){
              String temp = null ;
              System.out.print(info) ;
              try{
                     temp = this.buf.readLine() ;
              }catch(IOException e){
                     e.printStackTrace() ;
              }
              return temp ;
       }
       public int getInt(String info,String err){
              int temp = 0 ;
              String str = null ;
              boolean flag = true ;
              while(flag){
                     str = this.getString(info) ;
                     if(str.matches("^\\d+$")){
                            temp = Integer.parseInt(str) ;
                            flag = false ;
                     }else{
                            System.out.println(err) ;
                     }
              }
              return temp ;
       }
};
public class Hello{
   public static void main(String args[]){
              new Menu();
   }
};

程序还有几处性能问题需要优化。