JDBC返回List＜Map＞

ゞ浴缸里的玫瑰 2022-10-23 11:18 118阅读 0赞

直接贴代码。

import java.sql.*;
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    public class Jdbc { 
        public static void main(String[] args) { 
            final String URL = "jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8";
            final String USERNAME = "root";
            final String PASSWORD = "123456";
            Connection connection = null;
            PreparedStatement pstmt = null;
            ResultSet rs = null;
            List<Map<String, Object>> list = new ArrayList<>();
    
            try { 
                Class.forName("com.mysql.cj.jdbc.Driver");
                connection = DriverManager.getConnection(URL, USERNAME, PASSWORD);
                String sql = "select * from test";
                pstmt = connection.prepareStatement(sql);
                rs = pstmt.executeQuery();
                final ResultSetMetaData metaData = rs.getMetaData();
                final int columnCount = metaData.getColumnCount();
                //遍历加入
                while (rs.next()) { 
                    Map<String, Object> map = new HashMap<>();
                    for (int i = 1; i <= columnCount; i++) { 
                        map.put(metaData.getColumnLabel(i), rs.getObject(i));
                    }
                    list.add(map);
                }
            } catch (ClassNotFoundException e) { 
                e.printStackTrace();
            } catch (SQLException e) { 
                e.printStackTrace();
            } finally { 
                try { 
                    if (rs != null) rs.close();
                    if (pstmt != null) pstmt.close();
                    if (connection != null) connection.close();
                } catch (SQLException e) { 
                    e.printStackTrace();
                }
            }
            System.out.println(list);
        }
    
    }

数据库连接按照实际MYSQL驱动修改。