[Java]代码

import java.sql.DriverManager;

import java.sql.Connection;

import java.sql.SQLException;

import java.sql.ResultSet;

import java.sql.Statement;

public class PG{

public static void main(String []args){

System.out.println("PostgreSQL JDBC...");

try {

Class.forName("org.postgresql.Driver");

}catch (ClassNotFoundException e){

System.out.println("could not find postgreSQL JDBC Driver");

e.printStackTrace();

return;

}

Connection connection = null;

try {

connection = DriverManager.getConnection(

"jdbc:postgresql://localhost:5432/postgres",

"postgres",

"");

}catch (SQLException e){

System.out.println("Connection Failed");

e.printStackTrace();

return;

}

if (connection != null){

System.out.println("connect db successful!");

}else {

System.out.println("Failed to make conn!");

}

try {

Statement stmt = connection.createStatement();

ResultSet rs = stmt.executeQuery("SELECT 1 AS A");

if(rs!=null){

rs.next();

System.out.println(rs.getInt("a"));

}else {

System.out.println("null");

}

rs.close();

stmt.close();

connection.close();

}catch (Exception exp){

exp.printStackTrace();

}

}

}