ObjectOutputStream抛出StreamCorruptedException异常

柔光的暖阳◎ 2022-08-06 06:07 207阅读 0赞

问题如下：

import java.util.*;  
    import java.io.*;  
    public class cpm {  
        public static void main(String[] args) {  
            /*
             * 这一块是存对象的,首先调用3次。
            ObjectOutputStream oos = null;
            try {
                oos = new ObjectOutputStream(new FileOutputStream("E:/a.dat",true));
                for(int i = 0; i < 10; i++) {
                    oos.writeObject(new A(i,i));
                }
                oos.close();
            } catch(Exception ex){
                System.out.println(ex);
            }
            */
    
    
           /*存完对象之后,为什么调用这个读取只是读取出一组10个对象,而不是30个？？
           ObjectInputStream ois = null;
           try {
               ois = new ObjectInputStream(new FileInputStream("E:/a.dat"));
               while(true) {
                   A temp = (A)ois.readObject();
                   temp.show();
                }
            } catch(Exception ex) {}
           finally {
               try {
                   ois.close();
                }catch(Exception ex){}
            }
            */
        }
    }

解决方法有点奇怪， 首先要继承ObjectOutputStream类写一个子类，覆盖writeStreamHeader()方法，完整的代码如下：

package sdfg.drfg;
    
    import java.text.Collator;  
    import java.util.*;  
    import java.io.*;  
    public class cpm {  
        public static void main(String[] args) throws Exception {  
            // TODO Auto-generated method stub  
             //* 这一块是存对象的,首先调用3次。
            MyObjectOutputStream oos = null;
            try {
                oos = MyObjectOutputStream.getInstance(new File("E:/a.txt"),true);
                
                for(int i = 0; i < 2; i++) {
                    oos.writeObject(new A(i,i));
                }
                
                oos.writeObject(new A(5,6));
                oos.writeObject(new A(7,6));
                oos.close();
            } catch(Exception ex){
                ex.printStackTrace();
            }
            
           
           //存完对象之后,为什么调用这个读取只是读取出一组10个对象,而不是30个？？
           ObjectInputStream ois = null;
           try {
               ois = new ObjectInputStream(new FileInputStream("E:/a.txt"));
               while(true) {
                   A temp = (A)ois.readObject();
                   temp.show();
                }
            } catch(Exception ex) {
                System.out.println(ex);
            }
           finally {
               try {
                   ois.close();
                }catch(Exception ex){}
            }
            
        }
    }
    
    class A implements Serializable {
        private int x;
        private int y;
        public A(int x,int y) {
            this.x = x;
            this.y = y;
        }
        public void show() {
            System.out.println(x + " " + y);
        }
    }
    
    class MyObjectOutputStream extends ObjectOutputStream {
        static File f;
        static boolean _append;
        private MyObjectOutputStream(File file,boolean append) throws IOException {
            super(new FileOutputStream(file,append));
        }
        
        protected void writeStreamHeader() throws IOException {
            if(!f.exists()||f.length()==0||_append==false) {
                super.writeStreamHeader();
            }
            else {
                super.reset();
            }
        }
        
        public static MyObjectOutputStream getInstance(File file,boolean append) {
            f = file;
            _append = append;
            try {
                return new MyObjectOutputStream(file,append);
            } catch(IOException e) {
                e.printStackTrace();
            }
            return null;
        }
    }