java中将list、map对象写入文件 doudouhe的博客

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java中将list、map对象写入文件

(2014-03-17 17:39:36)

转载▼

标签：

it

分类： JAVA



public void writeObject() {

  try {


   HashMap<</span>String,String> map = new HashMap<</span>String,String>();

   map.put("name", "foolfish");



   FileOutputStream outStream = new FileOutputStream("E:/1.txt");

   ObjectOutputStream objectOutputStream = new ObjectOutputStream(outStream);


   objectOutputStream.writeObject(map);

   outStream.close();

   System.out.println("successful");

  } catch (FileNotFoundException e) {

   e.printStackTrace();

  } catch (IOException e) {

   e.printStackTrace();

  }

 }

这里我们将一个map对象插入一个txt文件当中。java的IO包当中提供了Object的文件流。代码很简单，我们下面来看一看从该文件当中读取这个对象吧



public void readObject(){

  FileInputStream freader;

  try {

   freader = new FileInputStream("E:/1.txt");

   ObjectInputStream objectInputStream = new ObjectInputStream(freader);

   HashMap<</span>String,String> map = new HashMap<</span>String,String>();

    map = (HashMap<</span>String, String>) objectInputStream.readObject();


    System.out.println("The name is " + map.get("name"));


  } 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();

  }


 }

代码也很简单，我们使用ObjectInputStream 的readobject的就可以读取文件中的对象，再按照封装对

象时候的类型进行强制转换一下。输出结果是aa foolfish。

上面提供的是对单个对象的存入和读取。对多个不同的对象该方法也适用。还是用代码来说明下吧。我们同时插入两个不同的对象，一个map，一个list。



public class ObjectToFile {

 public void writeObject() {

  try {


   HashMap<</span>String,String> map = new HashMap<</span>String,String>();

   map.put("name", "foolfish");


   List<</span>String> list = new ArrayList<</span>String>();

   list.add("hello");

   list.add("everyone");



   FileOutputStream outStream = new FileOutputStream("E:/1.txt");

   ObjectOutputStream objectOutputStream = new ObjectOutputStream(outStream);


   objectOutputStream.writeObject(map);

   objectOutputStream.writeObject(list);

   outStream.close();

   System.out.println("successful");

  } catch (FileNotFoundException e) {

   e.printStackTrace();

  } catch (IOException e) {

   e.printStackTrace();

  }

 }


 public void readObject(){

  FileInputStream freader;

  try {

   freader = new FileInputStream("E:/1.txt");

   ObjectInputStream objectInputStream = new ObjectInputStream(freader);

   HashMap<</span>String,String> map = new HashMap<</span>String,String>();

    map = (HashMap<</span>String, String>) objectInputStream.readObject();

    ArrayList<</span>String> list = new ArrayList<</span>String>();

    list = (ArrayList<</span>String>) objectInputStream.readObject();

    System.out.println("The name is " + map.get("name"));

    System.out.println("aa " + list.get(1));

  } 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();

  }


 }



 public static void main(String args[]){

  ObjectToFile of = new ObjectToFile();

  of.writeObject();

  of.readObject();

 }

}

java中将list、map对象写入文件 doudouhe的博客

java中将list、map对象写入文件

it

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