package util; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.SQLException; import java.util.ArrayList; import java.util.HashMap; import java.util.LinkedList; import java.util.List; import java.util.Map; import java.util.ResourceBundle; public class Jdbc { private static ResourceBundle res = ResourceBundle.getBundle("jdbc"); private static String url = res.getString("db.url"); private static String user = res.getString("db.user"); private static String psw = res.getString("db.password"); private static String driverClass = res.getString("driverClass"); private static Integer poolSize = Integer.parseInt(res.getString("poolSize")); private static LinkedList<Connection> connections = new LinkedList<Connection>(); private Connection conn; private ResultSet rs; private ResultSetMetaData md; private PreparedStatement ps; private List<Map<String,Object>> list; private Map<String,Object> map; static{ try { Class.forName(driverClass); } catch (ClassNotFoundException e) { e.printStackTrace(); } initConnPool(); } //初始化連接池 private static void initConnPool() { for (int i = 0; i < poolSize ; i++) { try { Connection conn = DriverManager.getConnection(url, user, psw); connections.add(conn); } catch (SQLException e) { e.printStackTrace(); } } } //拿出一個(gè)連接 private synchronized void getConnection() { conn = connections.removeFirst(); } //放回一個(gè)連接 private synchronized void backConnection(Connection connection,PreparedStatement ps,ResultSet rs) { try { if(ps!=null) ps.close(); if(rs!=null) rs.close(); connections.addLast(connection); } catch (SQLException e) { e.printStackTrace(); } } //執(zhí)行數(shù)據(jù)查詢語(yǔ)句 public List<Map<String,Object>> dql(String sql,Object...objs){ getConnection(); list = new ArrayList<Map<String,Object>>(); try { ps = conn.prepareStatement(sql); for (int i = 1; i <= objs.length; i++) { ps.setObject(i, objs[i]); } rs = ps.executeQuery(); md = rs.getMetaData(); while (rs.next()) { map = new HashMap<String,Object>(); for (int i = 1; i <= md.getColumnCount(); i++) { String key = md.getColumnName(i); Object value = rs.getObject(i); map.put(key, value); } list.add(map); } } catch (SQLException e) { e.printStackTrace(); }finally { backConnection(conn,ps,rs); } return list; } //執(zhí)行數(shù)據(jù)管理語(yǔ)句 public boolean dml(String sql,Object...objs){ getConnection(); try { ps = conn.prepareStatement(sql); for (int i = 1; i <= objs.length; i++) { ps.setObject(i, objs[i]); } return ps.executeUpdate()==1?true:false; } catch (SQLException e) { e.printStackTrace(); }finally { backConnection(conn,ps,rs); } return false; } }