Java對象的序列化與反序列化

Java對象序列化到檔案或資料庫

由于前段時間在學習Java web方面的知識，涉及到了session對象的鈍化與活化，對于将Java對象如何序列化到資料庫中一直沒有解決。今天看到一篇文章，得到了啟發，并做了改進，得出本文

一、準備一個Java類用于序列化與反序列化，該類必須實作Serializable接口

package ser_test;

import java.io.Serializable;
import java.util.Date;

public class Student implements Serializable{
    private static final long serialVersionUID = L;
    private String name;
    private Integer gender;
    private Date birthday;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getGender() {
        return gender;
    }
    public void setGender(Integer gender) {
        this.gender = gender;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

}
           

二、實作将Java對象序列化到檔案及從檔案讀取資料進行反序列化

package ser_test;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Date;

public class ObjectStoreToFile {
    public static void main(String[] args) throws Exception{
//      storeObjToFile();
        readObjFromFile();
    }

    /**
     * 将Java對象序列化到檔案
     * @throws IOException
     */
    public static void storeObjToFile() throws IOException {
        Student stu = new Student();
        stu.setName("Jimi");
        stu.setGender();
        stu.setBirthday(new Date());

        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("obj.txt"));
        oos.writeObject(stu);
    }
    /**
     * 從檔案讀取資料進行反序列化為Java對象
     * @throws IOException
     * @throws ClassNotFoundException
     */
    public static void readObjFromFile() throws IOException, ClassNotFoundException {
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream("obj.txt"));
        Student stu = (Student) ois.readObject();
        System.out.println(stu.getName() + "--" +stu.getGender() + "--" + stu.getBirthday());
    }
}
           

結果：

- 實作将Java對象序列化到資料庫及從資料庫擷取資料進行反序列化

資料庫表

package ser_test;

import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Date;

public class ObjectStoreToDb {
    public static void main(String[] args) {
        String driverClass = "com.mysql.jdbc.Driver";
        String url = "jdbc:mysql://localhost:3306/jeeweb?useunicode=true&charset=utf-8";
        String user = "root";
        String pwd = "password";
        try {
            Class.forName(driverClass);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        try {
            Connection connection = DriverManager.getConnection(url, user, pwd);
//          storeObjToDb(connection);
            readObjFromDb(connection);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 将Java對象儲存到資料庫
     * @param connection
     * @throws SQLException
     */
    public static void storeObjToDb(Connection connection) throws SQLException {
        Student stu = new Student();
        stu.setName("Jimi");
        stu.setGender();
        stu.setBirthday(new Date());
        String sql = " insert into stu(student) values(?)";
        PreparedStatement statement = connection.prepareStatement(sql);
        statement.setObject(, stu);
        statement.executeUpdate();
    }

    //讀取從資料庫擷取序列化後的二進制資料，反序列化為對應的Java對象
    public static void readObjFromDb(Connection connection) throws SQLException, 
        IOException, ClassNotFoundException {
        String sql = "select student from stu";
        PreparedStatement statement = connection.prepareStatement(sql);
        ResultSet resultSet = statement.executeQuery();
        while(resultSet.next()) {
            Blob blob = resultSet.getBlob();
            InputStream is = blob.getBinaryStream();
            ObjectInputStream ois = new ObjectInputStream(is);
            Student stu = (Student) ois.readObject();
            System.out.println(stu.getName() + "--" +stu.getGender() + "--" + stu.getBirthday());
        }
    }
}
           

結果：

注意：在看的部落格中，從資料庫擷取序列化的資料後，需要進行好幾次IO流的轉換，但是blob.getBinaryStream();的傳回值本來就是InputStream類型，而ObjectInputStream的構造函數剛好需要的也是一個InputStream類型的參數，是以直接進行使用即可

原文位址：http://blog.csdn.net/jeryjeryjery/article/details/70670103