package mypackage;

import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class JDBCUtils {

	private final String USERNAME = "root";
	private final String PWD = "admin";
	private final String DRIVER = "com.mysql.jdbc.Driver";
	private Connection connection;
	private java.sql.PreparedStatement preparedStatement;
	private ResultSet resultset;
	private String URL = "jdbc:mysql://localhost:3306/mydb";

	public JDBCUtils() {
		try {
			Class.forName(DRIVER);
			System.out.println("注册驱动成功");
		} catch (Exception e) {
			// TODO: handle exception
		}
	}

	// 定义获得数据库的链接

	public Connection getConnection() {
		try {
			connection = DriverManager.getConnection(URL, USERNAME, PWD);

		} catch (Exception e) {
			// TODO: handle exception
		}
		return connection;
	}

	/**
	 * 
	 * @param sql
	 * @param params
	 * @return
	 * @throws SQLException
	 */
	public boolean updateByPrepareStatement(String sql, List<Object> params)
			throws SQLException {
		boolean flag = false;
		int result = -1;// 受影响的行数
		int index = 1;
		preparedStatement = connection.prepareStatement(sql);
		if (params != null && !params.isEmpty()) {
			for (int i = 0; i < params.size(); i++) {
				preparedStatement.setObject(index++, params.get(i));
			}
		}
		result = preparedStatement.executeUpdate();
		flag = result > 0 ? true : false;
		return flag;
	}

	/**
	 * 查询返回单条记录
	 * 
	 * @param sql
	 * @param params
	 * @return
	 * @throws SQLException
	 */
	public Map<String, Object> findSimpleResult(String sql, List<Object> params)
			throws SQLException {
		Map<String, Object> map = new HashMap<String, Object>();
		int index = 1;
		preparedStatement = connection.prepareStatement(sql);
		if (params != null && !params.isEmpty()) {
			for (int i = 0; i < params.size(); i++) {
				preparedStatement.setObject(index++, params.get(i));
			}
		}
		resultset = preparedStatement.executeQuery();// 返回查询结果
		ResultSetMetaData metaData = resultset.getMetaData();
		int col_len = metaData.getColumnCount();
		while (resultset.next()) {
			for (int i = 0; i < col_len; i++) {
				String col_name = metaData.getColumnName(i + 1);
				Object col_values = resultset.getObject(col_name);
				if (col_values == null) {
					col_values = "";
				}
				map.put(col_name, col_values);
			}
		}
		return map;
	}

	/**
	 * 查找多条记录
	 * 
	 * @return
	 */

	public List<Map<String, Object>> findMoreResultString(String sql,
			List<Object> params) throws SQLException {
		List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
		int index = 1;
		preparedStatement = connection.prepareStatement(sql);
		if (params != null && !params.isEmpty()) {
			for (int i = 0; i < params.size(); i++) {
				preparedStatement.setObject(index++, params.get(i));
			}
		}
		resultset = preparedStatement.executeQuery();// 返回查询结果
		ResultSetMetaData metaData = resultset.getMetaData();
		int col_len = metaData.getColumnCount();
		while (resultset.next()) {
			Map<String, Object> map = new HashMap<String, Object>();
			for (int i = 0; i < col_len; i++) {
				String col_name = metaData.getColumnName(i + 1);
				Object col_values = resultset.getObject(col_name);
				if (col_values == null) {
					col_values = "";
				}
				map.put(col_name, col_values);
			}

			list.add(map);
		}

		return list;
	}

	// 利用反射机制
	/**
	 * 通过反射机制访问数据库
	 * 
	 * @param sql
	 * @param params
	 * @param cls
	 * @return
	 * @throws SQLException
	 * @throws Exception
	 * @throws IllegalAccessException
	 */
	public <T> List<T> findMore(String sql, List<Object> params, Class<T> cls)
			throws SQLException, Exception {
		List<T> list = new ArrayList<T>();
		int index = 1;
		Object resultObject=null;
		preparedStatement = connection.prepareStatement(sql);
		if (params != null && !params.isEmpty()) {
			for (int i = 0; i < params.size(); i++) {
				preparedStatement.setObject(index++, params.get(i));
			}
		}
		resultset = preparedStatement.executeQuery();// 返回查询结果
		ResultSetMetaData metaData = resultset.getMetaData();
		int col_len = metaData.getColumnCount();
		while (resultset.next()) {
			resultObject = cls.newInstance();
			for (int i = 0; i < col_len; i++) {
				String col_name = metaData.getColumnName(i+1);
				Object col_values = resultset.getObject(col_name);
				if (col_values == null) {
					col_values = "";
				}
				Field field = cls.getDeclaredField(col_name);
				field.setAccessible(true);
				field.set(resultObject, col_values);
			}
			list.add((T) resultObject);
		}

		return list;
	}

	/**
	 * 关闭数据库连接
	 */
	public void releaseConnection() {

		if (resultset != null)
			try {
				resultset.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		if (preparedStatement != null)
			try {
				preparedStatement.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		if (connection != null)
			try {
				connection.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
	}

	/**
	 * 
	 * @param args
	 * @throws SQLException
	 */
	public static void main(String[] args) throws SQLException {
		JDBCUtils jdbcUtils = new JDBCUtils();
		jdbcUtils.getConnection();

		
		/*
		 * String sql = "insert into userinfo(username,pwd) values (?,?)";
		 * List<Object> params = new ArrayList<Object>(); params.add("admin");
		 * params.add("admin"); boolean flag =
		 * jdbcUtils.updateByPrepareStatement(sql, params);
		 * System.out.println(flag);
		 */
		String sql = "select * from userinfo where id=?";
		String sql1 = "select * from userinfo";
		List<Object> params = new ArrayList<Object>();
		/*params.add(1);
		Map map = jdbcUtils.findSimpleResult(sql, params);

		try {
			List list = jdbcUtils.findMoreResultString(sql1, null);
			System.out.println(map);
			System.out.println(list);
		}

		catch (Exception e) {
			e.printStackTrace();
		} finally {
			jdbcUtils.releaseConnection();
		}*/
		try {
			System.out.println("---fsdfas");
		List<userinfo> userlist=	jdbcUtils.findMore(sql1, null, userinfo.class);
		System.out.println("---"+userlist);
		} catch (Exception e) {
			e.printStackTrace();
		}
		finally {
			jdbcUtils.releaseConnection();
		}
	}
}

androidj常用数据库操作JDBC Utils,布布扣,bubuko.com

androidj常用数据库操作JDBC Utils