[JavaSE] Paquete JDBC

comprobar frase

package com.hzyc.design;

import java.sql.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

public class JDBCTools {
    
    
    private String url = "jdbc:mysql://localhost:3308/hzyc98";
    private String username = "root";
    private String userpassword = "mysql";
    private Connection conn;
    private Statement stmt;
    private ResultSet reSet;

    //连接的封装方法
    private void connect() {
    
    
        try {
    
    
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection(url, username, userpassword);
            stmt = conn.createStatement();
        } catch (Exception e) {
    
    
            e.printStackTrace();
        }
    }

    //关闭的封装方法
    private void close() {
    
    
        try {
    
    
            if (reSet != null) {
    
    
                reSet.close();
            }
            if (stmt != null) {
    
    
                stmt.close();
            }
            if (conn != null) {
    
    
                conn.close();
            }
        } catch (Exception e) {
    
    
            e.printStackTrace();
        }
    }

    /**
     * 操作查询语句，查询到该表之后返回一个集合
     * 返回一个类型为：ArrayList<Map<String, String>>的集合
     * 一条List代表着一行语句，这一行语句由Map，也就是表头和内容所组成
     *
     * @param sql 一条SQL语句，（select语句）
     */
    public ArrayList<Map<String, String>> find(String sql) {
    
    
        ArrayList<Map<String, String>> rsList = null;
        try {
    
    
            rsList = new ArrayList<Map<String, String>>();
            connect();
            reSet = stmt.executeQuery(sql);
            //获取结果集
            ResultSetMetaData rsmd = reSet.getMetaData();
            //一个reSet就是火车列表的一行数据。
            while (reSet.next()) {
    
    
                Map<String, String> reSetMap = new HashMap<String, String>();

                for (int c = 1; c <= rsmd.getColumnCount(); c++) {
    
    
                    String columeName = rsmd.getColumnName(c);
                    String value = reSet.getString(columeName);
                    reSetMap.put(columeName, value);
                }
                rsList.add(reSetMap);
            }
        } catch (Exception e) {
    
    
            e.printStackTrace();
        } finally {
    
    
            close();
        }
        return rsList;
    }
    
    //更新数据库，使用stmt载体
    public void update(String sql) {
    
    
        try {
    
    
            connect();
            stmt.executeUpdate(sql);
        } catch (Exception e) {
    
    
            e.printStackTrace();
        } finally {
    
    
            close();
        }
    }

}