package cn.itcast.Reflect;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import cn.itcast.JdbcUtils;

//反射获取数据库内容

public class ORMTest {

	public static void main(String[] args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, SQLException, InstantiationException {

		User2 user = (User2)getObject("select id as Id,username as Username,password as Password from t_user where id=1",User2.class);

		System.out.println(user.getUsername());

	}

	public static Object getObject(String sql,Class clazz) throws SQLException,

			IllegalAccessException, IllegalArgumentException,

			InvocationTargetException, InstantiationException {

		Connection conn = null;

		PreparedStatement ps = null;

		ResultSet rs = null;

		try {

			conn = JdbcUtils.getConnection();

			ps = conn.prepareStatement(sql);

			rs = ps.executeQuery();

			java.sql.ResultSetMetaData rsmd = rs.getMetaData();

			int count = rsmd.getColumnCount();

			String[] colNames = new String[count];

			for (int i = 1; i <= count; i++) {

				colNames[i - 1] = rsmd.getColumnLabel(i);

			}

			Object obj = null;

			Method[] ms = clazz.getMethods();

			if (rs.next()) {

				obj = clazz.newInstance();

				for (int i = 0; i < colNames.length; i++) {

					String colName = colNames[i];

					String methodName = "set" + colName;

					for (Method m : ms) {

						if (methodName.equals(m.getName())) {

							m.invoke(obj, rs.getObject(colName));

						}

					}

				}

			}

			return obj;

		} finally {

			JdbcUtils.free(rs, ps, conn);

		}

	}

}