java代码连接数据库编码实现

依赖包：

compile group: 'mysql', name: 'mysql-connector-java', version: '5.1.38'
compile group: 'org.mongodb', name: 'mongo-java-driver', version: '4.2.3'
compile group: 'com.oracle.database.jdbc', name: 'ojdbc8', version: '19.8.0.0'

public static Connection getConnection() {

    Connection conn = null;
    try {
        String url = "jdbc:oracle:thin:@127.0.0.1:1521:orcl";
        String user = "scott";
        String password = "tiger";

        Class.forName("oracle.jdbc.driver.OracleDriver");// 加载数据驱动
        conn = DriverManager.getConnection(url, user, password);// 连接数据库

    } catch (ClassNotFoundException e) {
        e.printStackTrace();
        System.out.println("加载数据库驱动失败");
    } catch (Exception e) {
        e.printStackTrace();
        System.out.println("连接数据库失败");
    }
    return conn;
}

mysql:

public static final String url = "jdbc:mysql://192.168.31.150/information_schema";

public static final String name = "com.mysql.jdbc.Driver";  
public static final String user = "root";  
public static final String password = "";  

public static Connection conn = null;  
public static PreparedStatement pst = null;  
public static ResultSet  ret  = null;


public static Connection getConnection(String url,String user,String password) throws Exception{
    try {
         Class.forName(name);
         Connection connection = DriverManager.getConnection(url,user,password);//获取连接  
         if(null == connection) {
             throw new Exception("can not connect mysql");
         }
         return connection;
    } catch (Exception e) {
        throw e;
    }
}

mongo:

//不通过认证获取连接数据库对象

@SuppressWarnings("resource")
public static MongoDatabase getConnect(String ip,int port,String databaseName){
    //连接到 mongodb 服务
    MongoClient mongoClient = new MongoClient(ip, port);
    //连接到数据库
    MongoDatabase mongoDatabase = mongoClient.getDatabase(databaseName);
    //返回连接数据库对象
    return mongoDatabase;
}