Java使用JDBC连接postgresql数据库示例

package tool;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class PsqlConnectionTool {
 private String url = "jdbc:postgresql://xxx.xxx.xxx.xxx:5432/testdb";
 private String username = "postgres";
 private String password = "postgres";
 private Connection connection = null;
 public Connection getConn() {
  try {
   Class.forName("org.postgresql.Driver").newInstance();
   connection = DriverManager.getConnection(url, username, password);
  } catch (InstantiationException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IllegalAccessException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (ClassNotFoundException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  return connection;
 }
 public ResultSet query(Connection conn, String sql) {
  PreparedStatement pStatement = null;
  ResultSet rs = null;
  try {
   pStatement = conn.prepareStatement(sql);
   rs = pStatement.executeQuery();
  } catch (SQLException e) {
   e.printStackTrace();
  }
  return rs;
 }
 public boolean queryUpdate(Connection conn, String sql) {
  PreparedStatement pStatement = null;
  int rs = 0;
  try {
   pStatement = conn.prepareStatement(sql);
   rs = pStatement.executeUpdate();
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  if (rs > 0) {
   return true;
  }
  return false;
 }
 public static void main(String[] args) throws SQLException {
  PsqlConnectionTool pgtool = new PsqlConnectionTool();
  Connection myconn = pgtool.getConn();
  pgtool.queryUpdate(myconn, "insert into test values (1,'smoon','man')");
  ResultSet rs = pgtool.query(myconn, "select * from test");
  while(rs.next()){
   int id = rs.getInt("id");
   String name = rs.getString("name");
   String gender = rs.getString("gender");
   System.out.println("id:"+id+" 姓名："+name+" 性别："+gender);
   myconn.close();
  }
 }
}