java如何将多个hashmap写入文件并单个存取？

直接上代码：主要就是使用ObjectOutputStream；多个Map放到List中去，具体可以变通，单个存取，也可以将多个Map放到一个新的Map中去。

public void writeObject(){
        try {
            Map<String, Object> map1 = new HashMap<String, Object>();
            map1.put("a1", "a-aaa");
            map1.put("a2", "a-bbb");
            
            Map<String, Object> map2 = new HashMap<String, Object>();
            map2.put("b1", "b-aaa");
            map2.put("b2", "b-bbb");
            
            List<Map<String, Object>> list=new ArrayList<Map<String,Object>>();
            list.add(map1);
            list.add(map2);
            FileOutputStream outStream = new FileOutputStream("E:/1.txt");
            ObjectOutputStream objectOutputStream = new ObjectOutputStream(
                    outStream);

            objectOutputStream.writeObject(list);
            outStream.close();
            System.out.println("successful");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    public void readObject(){
        FileInputStream freader;
        try {
            freader = new FileInputStream("E:/1.txt");
            ObjectInputStream objectInputStream = new ObjectInputStream(freader);
            HashMap<String,Object> map = new HashMap<String,Object>();
            
            List<Map<String, Object>> list=(List<Map<String, Object>>)objectInputStream.readObject();
            for (Map<String, Object> map2 : list) {
                System.out.println(map2.toString());
            }
        } 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();
        }
        
    }