jdbc连接数据库

1. 准备工作

• 先创建工程，把数据库相关的驱动包复制到WEB-INF/lib下

• 创建一个数据库工具类

  采用固定方式设置数据库驱动连接信息

/**DataBaseConnection
 * 用于连接数据库
 * @author Administrator
 * @since 2019-11-29 17:59:55
 * @category 获取数据库连接对象
 */
public class DataBaseConnection {
    private static final String DRIVER = "oracle.jdbc.driver.OracleDriver";
    private static final String URL = "jdbc:oracle:thin:@localhost:1521:orcl";
    private static final String USER = "xiaotang";
    private static final String PWD = "123456";
    
    private Connection conn = null;
    
    public Connection getConnection() {
        try {
            Class.forName(DRIVER);
                         System.out.println("数据库连接中......");
            conn = DriverManager.getConnection(URL, USER, PWD);
                        System.out.println("数据库连接成功!");
        } catch (ClassNotFoundException e) {
            System.out.println("数据库驱动加载失败");
        } catch (SQLException e) {
            System.out.println("数据库连接失败");
        }
        return conn;
    }
    
    public void close(Connection conn,PreparedStatement pstmt,ResultSet rs) {
        //关闭资源
        try {
            if(rs!=null) {
                rs.close();
            }
            if(pstmt!=null) {
                pstmt.close();
            }
            if(conn!=null) {
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        DataBaseConnection db=new DataBaseConnection();
        System.out.println(db.getConnection());
    }
    
}

采用Properties 对象来读取数据库配置信息
在src下新建一个jdbc.properties文件

oracle.driver=oracle.jdbc.driver.OracleDriver
oracle.url=jdbc:oracle:thin:@localhost:1521:orcl
oracle.username=xiaotang
oracle.password=123456

然后新建工具类读取数据库信息，创建连接对象

public Connection getConnectionpp() {
        try {
            Properties pp=new Properties();
            InputStream in =DataBaseConnection.
                    class.getClassLoader()
                    .getResourceAsStream("jdbc.properties");
                pp.load(in);
            String driver=pp.getProperty("oracle.driver");
            String url=pp.getProperty("oracle.url");
             System.out.println("数据库连接中......");
            Class.forName(driver);
            conn = DriverManager.getConnection(url,
                    pp.getProperty("oracle.username"),
                    pp.getProperty("oracle.password")
                    );
               System.out.println("数据库连接成功!");
        } catch (Exception e) {
            System.out.println("数据库连接失败");
        }
        return conn;
    }

效果同上

其它数据库连接信息

###ORACLE
oracle.driver_class_name=oracle.jdbc.driver.OracleDriver
oracle.url=jdbc:oracle:thin:@localhost:1521:orcl
oracle.username=root
oracle.password=12345

###DB
db.driver_class_name=com.ibm.db2.jdbc.app.DB2Driver 
db.url=jdbc:db2://localhost:5000/sample
db.username=root
db.password=12345

###Mssql
mssql.driver_class_name=net.sourceforge.jtds.jdbc.Driver
mssql.url=jdbc:jtds:sqlserver://127.0.0.1:1433/databaseName
mssql.username=root
mssql.password=12345

###Sybase
sybase.driver_class_name=com.sybase.jdbc.SybDriver
sybase.url=jdbc:sybase:Tds:localhost:5007/myDB
sybase.usernamename=root
sybase.password=12345


###Informix
informix.driver_class_name=com.informix.jdbc.IfxDriver
informix.url=jdbc:informix-sqli://123.45.67.89:1533/myDB:INFORMIXSERVER=myserver
informix.username=testusername
informix.password=testpassword

###postgresql
postgresql.driver_class_name=org.postgresql.Driver
postgresql.url=jdbc:postgresql://localhost/myDB
postgresql.username=testusername
postgresql.password=testpassword

###MYSQL
mysql.driver_class_name=org.gjt.mm.mysql.Driver,com.mysql.jdbc.Driver,com.mysql.cj.jdbc.Driver
mysql.url=jdbc:mysql://localhost:3306/myDB?useUnicode=true&characterEncoding=utf-8
mysql.username=soft
mysql.password=soft1234

###h2
h2.driver_class_name=org.h2.Driver
h2.url=jdbc:h2:~/test
h2.username=sa
h2.password=123