JDBC连接数据库

Posted 2022-02-20 lixiaofeng1650062546

Jdbc 连接数据库

1 连接字符串

SQLite

Class.forName("org.sqlite.JDBC"); 
Connection conn =DriverManager.getConnection("jdbc:sqlite:zieckey.db");

mysql (http://www.mysql.com)

Class.forName( "org.gjt.mm.mysql.Driver" ); 
Connection conn = DriverManager.getConnection( "jdbc:mysql://MyDbComputerNameOrIP:3306/myDatabaseName", sUsr, sPwd );

PostgreSQL (http://www.de.postgresql.org)

Class.forName( "org.postgresql.Driver" ); 
Connection conn = DriverManager.getConnection( "jdbc:postgresql://MyDbComputerNameOrIP/myDatabaseName", sUsr, sPwd );

Oracle (http://www.oracle.com/ip/deploy/database/oracle9i/)

Class.forName( "oracle.jdbc.driver.OracleDriver" ); 
Connection conn = DriverManager.getConnection( "jdbc:oracle:thin:@MyDbComputerNameOrIP:1521:ORCL", sUsr, sPwd );

Microsoft SQLServer (http://jtds.sourceforge.net)

Class.forName( "net.sourceforge.jtds.jdbc.Driver" ); 
cn = DriverManager.getConnection( "jdbc:jtds:sqlserver://MyDbComputerNameOrIP:1433/master", sUsr, sPwd );

Microsoft SQLServer (http://www.microsoft.com)

Class.forName( "com.microsoft.jdbc.sqlserver.SQLServerDriver" ); 
Connection conn = DriverManager.getConnection( "jdbc:microsoft:sqlserver://MyDbComputerNameOrIP:1433;databaseName=master",sUsr, sPwd );

2 释放资源的写法

public class DBUtil 
    public static void close(Connection conn) 
        close(conn, null, null);
    
    public static void close(Connection conn, Statement stmt, ResultSet resultSet) 
        if (resultSet != null) 
            try 
                resultSet.close();
             catch (Exception ignored) 
        
        if (stmt != null) 
            try 
                stmt.close();
             catch (Exception ignored) 
        
        if (conn != null) 
            try 
                conn.close();
             catch (Exception ignored) 
        
    

3 连接 SQLite3 的示例

public void sqliteJDBCDemo() 
    Connection conn = null;
    try 
        // 1. 驱动
        Class.forName("org.sqlite.JDBC");
        // 2. 打开连接
        conn = DriverManager.getConnection("jdbc:sqlite:e:/data/student.sqlite3");

        // 3. 操作
        Statement statement = conn.createStatement();
        ResultSet resultSet = statement.executeQuery("select name, weixin, score from student");
        while (resultSet.next()) 
            System.out.printf("Name: %s, Weixin: %s, Score: %f\n",
                    resultSet.getString(1),
                    resultSet.getString(2),
                    resultSet.getFloat(3));
        
     catch (ClassNotFoundException e) 
        System.out.println("1. 驱动加载失败");
     catch (SQLException e) 
        System.out.println("2. 数据库异常");
     finally 
        // 4. 释放资源
        if (conn != null)
            try 
                conn.close();
             catch (SQLException e) 
                e.printStackTrace();