利用结果集元数据将查询结果封装为map

package it.cast.jdbc;

import java.sql.Connection;
import java.sql.ParameterMetaData;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

public class ResultSetMetaTest {

    public static void main(String[] args) throws SQLException {
        
        Map<String,Object> map = read("select * from user where id=2");
        System.out.println(map);
    }

    static Map<String, Object> read(String sql) throws SQLException {

        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;

        try {
            conn = jdbcUtils.getConnection();
            ps = conn.prepareStatement(sql);
            rs = ps.executeQuery();

            ResultSetMetaData rsmd = rs.getMetaData();

            // 得出有多少列
            int count = rsmd.getColumnCount();

            String[] colNames = new String[count];

            for (int i = 1; i <= count; i++) {
                // System.out.print(rsmd.getColumnClassName(i)+"\t");
                // System.out.print(rsmd.getColumnName(i)+"\t");
                // System.out.println(rsmd.getColumnLabel(i)+"\t");
                colNames[i-1] = rsmd.getColumnName(i);
            }

            Map<String, Object> data = null;

            while (rs.next()) {
                data = new HashMap<String, Object>();
                
                for (int j = 0; j < colNames.length; j++) {
                    data.put(colNames[j], rs.getObject(colNames[j]));
                }
            }

            return data;
        } finally {
            jdbcUtils.free(rs, ps, conn);
        }
    }
}