rsmd.java

各种数据保存：字符型

package cn.itcast.jdbc;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

import cn.itcast.domain.User;

public class RSMD {

	/**
	 * @param args
	 * @throws SQLException
	 * @throws IllegalAccessException
	 * @throws InstantiationException
	 * @throws InvocationTargetException
	 * @throws IllegalArgumentException
	 */
	public static void main(String[] args) throws Exception,
			IllegalArgumentException, InvocationTargetException {
		String sql = "select id as Id, name as Name, birth_day as BirthDay, age as Age from user";
		List list = testData(sql, User.class);
		for (Iterator iter = list.iterator(); iter.hasNext();) {
			User user = (User) iter.next();
			System.out.print(user.getId());
			System.out.print(user.getName());
			System.out.print(user.getAge());
			System.out.print(user.getBirthDay());
			System.out.println();
		}
	}

	static List testData(String sql, Class clazz) throws Exception {
		Connection conn = null;
		Statement st = null;
		ResultSet rs = null;
		List list = new ArrayList();
		try {
			conn = JdbcUtils.getConnection();
			st = conn.createStatement();
			rs = st.executeQuery(sql);

			ResultSetMetaData rsmd = rs.getMetaData();
			int colCount = rsmd.getColumnCount();
			String[] colNames = new String[colCount];
			for (int i = 0; i < colCount; i++) {
				colNames[i] = rsmd.getColumnLabel(i + 1);
			}
			System.out.println(Arrays.asList(colNames));

			while (rs.next()) {
				Object obj = clazz.newInstance();
				for (int i = 0; i < colCount; i++) {
					Method m = findMethod(colNames[i], clazz);
					if (m != null)
						try {
							m.invoke(obj, rs.getObject(colNames[i]));
						} catch (Exception e) {
							System.out.println(colNames[i] + " error!");
							System.out.println(rsmd.getColumnType(i + 1));
							throw e;
						}
				}
				list.add(obj);
			}
		} finally {
			JdbcUtils.realse(rs, st, conn);
		}
		return list;
	}

	static Method findMethod(String colName, Class clazz) {
		Method[] ms = clazz.getDeclaredMethods();
		colName = "set" + colName;
		for (int i = 0; i < ms.length; i++)
			if (colName.equals(ms[i].getName()))
				return ms[i];
		return null;
	}
}