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2010-06-01T06:35:02Z

1 версия

в 18:01, 31 мая 2010

2010-05-31T18:01:44Z

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== How to serialize/de-serialize a Java object to the MySQL database. ==



<source lang="java">
/*
* mysql> CREATE TABLE java_objects (
* id INT AUTO_INCREMENT,
* name varchar(128),
* object_value BLOB,
* primary key (id));
**/
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
public class SerializeJavaObjects_MySQL {
static final String WRITE_OBJECT_SQL = "INSERT INTO java_objects(name, object_value) VALUES (?, ?)";
static final String READ_OBJECT_SQL = "SELECT object_value FROM java_objects WHERE id = ?";
public static Connection getConnection() throws Exception {
String driver = "org.gjt.mm.mysql.Driver";
String url = "jdbc:mysql://localhost/databaseName";
String username = "root";
String password = "root";
Class.forName(driver);
Connection conn = DriverManager.getConnection(url, username, password);
return conn;
}
public static long writeJavaObject(Connection conn, Object object) throws Exception {
String className = object.getClass().getName();
PreparedStatement pstmt = conn.prepareStatement(WRITE_OBJECT_SQL);
// set input parameters
pstmt.setString(1, className);
pstmt.setObject(2, object);
pstmt.executeUpdate();
// get the generated key for the id
ResultSet rs = pstmt.getGeneratedKeys();
int id = -1;
if (rs.next()) {
id = rs.getInt(1);
}
rs.close();
pstmt.close();
System.out.println("writeJavaObject: done serializing: " + className);
return id;
}
public static Object readJavaObject(Connection conn, long id) throws Exception {
PreparedStatement pstmt = conn.prepareStatement(READ_OBJECT_SQL);
pstmt.setLong(1, id);
ResultSet rs = pstmt.executeQuery();
rs.next();
Object object = rs.getObject(1);
String className = object.getClass().getName();
rs.close();
pstmt.close();
System.out.println("readJavaObject: done de-serializing: " + className);
return object;
}
public static void main(String args[])throws Exception {
Connection conn = null;
try {
conn = getConnection();
System.out.println("conn=" + conn);
conn.setAutoCommit(false);
List<Object> list = new ArrayList<Object>();
list.add("This is a short string.");
list.add(new Integer(1234));
list.add(new Date());
long objectID = writeJavaObject(conn, list);
conn.rumit();
System.out.println("Serialized objectID => " + objectID);
List listFromDatabase = (List) readJavaObject(conn, objectID);
System.out.println("[After De-Serialization] list=" + listFromDatabase);
} catch (Exception e) {
e.printStackTrace();
} finally {
conn.close();
}
}
}

</source>

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Java/Database SQL JDBC/Object Serialization - История изменений

Admin: 1 версия

в 18:01, 31 мая 2010