1,从磁盘中读取数据：

package com.wjb.demo;
import java.io.*;
/**
 * Created by wjb on 2017/5/5.
 */
public class InputStreamTest {

    public static void main(String[] args) {
        File file = new File("F:\\Wjb.java");
        try {
            BufferedReader bf = new BufferedReader(new InputStreamReader(new FileInputStream(file),"UTF-8"));
            String info = null;
            StringBuffer sb = new StringBuffer();
            while((info = bf.readLine()) != null){
                sb.append(info);
            }
            bf.close();
            System.out.println(sb.toString());
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

2,序列化与反序列化：

对象必须实现serializable接口

package com.wjb.demo;

import java.io.*;

/**
 * Created by wjb on 2017/5/5.
 */
public class SerializableTest implements Serializable {
    private static final long serialVersionUID = 4466065210971417002L;
    public int num = 100;

    public static void main(String[] args) throws IOException {
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("F:\\aaaa.dat"));
        SerializableTest serializableTest = new SerializableTest();
        oos.writeObject(serializableTest);
        oos.flush();

        ObjectInputStream ois = new ObjectInputStream(new FileInputStream("F:\\aaaa.dat"));
        try {
            SerializableTest serializableTest2 = (SerializableTest) ois.readObject();
            System.out.println(serializableTest2.num);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}