11 连接|关闭 数据库方法封装,并测试

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/*
 * 连接|关闭 数据库方法封装
 */
public class JDBCUtil {
    
    /*
     * 获得MySQl的连接
     */
    public static Connection getConnection(){
        
        try {
            Class.forName("com.mysql.jdbc.Driver");
            return DriverManager.getConnection(
                    "jdbc:mysql://localhost:3306/test","root","123456");
            
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
            return null;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        }
    }
    
    /*
     * 关闭rs,stmt,ps,conn
     */
    public static void close(ResultSet rs,PreparedStatement stmt,Connection conn){
        //关闭顺序遵循:ResultSet-->Statement->Connection
        if(rs != null){
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        if(stmt != null){
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

测试方法封装是否可用

import java.sql.*;


public class TestJDBCUtil {

    /**
     * 测试方法封装是否可用
     */
    public static void main(String[] args) {
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        
        try {
            conn = JDBCUtil.getConnection();
            
            ps = conn.prepareStatement("select * from user where uid=?");
            ps.setInt(1, 1);
            if(ps.execute()){
                rs = ps.getResultSet();
                while(rs.next()){
                    System.out.println(rs.getInt(1));
                }
            }
            
            System.out.println("TestJDBCUtil.main()");
            
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            JDBCUtil.close(rs, ps, conn);
        }

    }
}