package com.zhangguo.springmvc08.utils; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; 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.sql.Statement; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class JDBCUtil { public static String DRIVER="com.mysql.jdbc.Driver"; public static String URL="jdbc:mysql://127.0.0.1:3306/schoolmis?useUnicode=true&characterEncoding=UTF-8"; public static String USER_NAME="root"; public static String PASSWORD="pwd"; { try { Class.forName(DRIVER); } catch (ClassNotFoundException e) { e.printStackTrace(); } } private JDBCUtil() { } /** * 获得连接 * * Connection getconnnection() { Connection con = null; try { con = DriverManager.getConnection(URL, USER_NAME, PASSWORD); } catch (SQLException e) { e.printStackTrace(); } return con; } /** * 关闭连接 * * @param rs * @param st * @param con close(ResultSet rs, Statement st, Connection con) { try { try { if (rs != null) { rs.close(); } } finally { try { if (st != null) { st.close(); } } finally { if (con != null) con.close(); } } } catch (SQLException e) { e.printStackTrace(); } } /** * 关闭连接 * * @param rs close(ResultSet rs) { Statement st = null; Connection con = null; try { try { if (rs != null) { st = rs.getStatement(); rs.close(); } } finally { try { if (st != null) { con = st.getConnection(); st.close(); } } finally { if (con != null) { con.close(); } } } } catch (SQLException e) { e.printStackTrace(); } } /** * 关闭连接 * * @param st * @param con close(Statement st, Connection con) { try { try { if (st != null) { st.close(); } } finally { if (con != null) con.close(); } } catch (SQLException e) { e.printStackTrace(); } } /** * insert/update/delete * 增加/更新/删除 * * @param sql 数据库语句 * @param args 可变参数（可以不带参数，可以带0-n个参数） * update(String sql, Object... args) { int result = 0; Connection con = getconnnection(); PreparedStatement ps = null; try { ps = con.prepareStatement(sql); if (args != null) { for (int i = 0; i < args.length; i++) { ps.setObject((i + 1), args[i]); } } result = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } finally { close(ps, con); } return result; } /** * query, because need to manually close the resource, so not recommended * for use it * * @param sql * @param args * @return ResultSet */ @Deprecated ResultSet query(String sql, Object... args) { ResultSet result = null; Connection con = getconnnection(); PreparedStatement ps = null; try { ps = con.prepareStatement(sql); if (args != null) { for (int i = 0; i < args.length; i++) { ps.setObjec常德淘宝优惠券t((i + 1), args[i]); } } result = ps.executeQuery(); } catch (SQLException e) { e.printStackTrace(); } return result; } /** * Query a single record * 查询单个记录 * @param sql * @param args * @return Map<String,Object> Map<String, Object> queryForMap(String sql, Object... args) { Map<String, Object> result = new HashMap<String, Object>(); List<Map<String, Object>> list = queryForList(sql, args); if (list.size() > 0) { result = list.get(0); } return result; } /** * Query a single record * 查询单个记录返回强类型对象 * @param sql * @param args * @return <T> //泛型 <T> T queryForObject(String sql, Class<T> clz, Object... args) { T result = null; List<T> list = queryForList(sql, clz, args); if (list.size() > 0) { result = list.get(0); } return result; } /** * Query a single record * * @param sql * @param args * @return List<Map<String,Object>> List<Map<String, Object>> queryForList(String sql, Object... args) { List<Map<String, Object>> result = new ArrayList<Map<String, Object>>(); Connection con = null; ResultSet rs = null; PreparedStatement ps = null; try { con = getconnnection(); ps = con.prepareStatement(sql); if (args != null) { for (int i = 0; i < args.length; i++) { ps.setObject((i + 1), args[i]); } } rs = ps.executeQuery(); ResultSetMetaData rsmd = rs.getMetaData(); int columnCount = rsmd.getColumnCount(); while (rs.next()) { Map<String, Object> map = new HashMap<String, Object>(); for (int i = 1; i <= columnCount; i++) { map.put(rsmd.getColumnLabel(i), rs.getObject(i)); } result.add(map); } } catch (SQLException e) { e.printStackTrace(); } finally { close(rs, ps, con); } return result;昌都淘宝优惠券 } /** * Query records * 查询多个对象，返回强类型集合 * @param sql * @param args * @return List<T> <T> List<T> queryForList(String sql, Class<T> clz, Object... args) { List<T> result = new ArrayList<T>(); Connection con = null; PreparedStatement ps = null; ResultSet rs = null; try { con = getconnnection(); ps = con.prepareStatement(sql); if (args != null) { for (int i = 0; i < args.length; i++) { ps.setObject((i + 1), args[i]); } } rs = ps.executeQuery(); ResultSetMetaData rsmd = rs.getMetaData(); int columnCount = rsmd.getColumnCount(); while (rs.next()) { T obj = clz.newInstance(); for (int i = 1; i <= columnCount; i++) { String columnName = rsmd.getColumnName(i); String methodName = "set" + columnName.substring(0, 1).toUpperCase() + columnName.substring(1, columnName.length()); Method method[] = clz.getMethods(); for (Method meth : method) { if (methodName.equals(meth.getName())) { meth.invoke(obj, rs.getObject(i)); } } } result.add(obj); } } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (SQLException e) { e.printSt榆林淘宝优惠券ackTrace(); } catch (IllegalArgumentException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } finally { close(rs, ps, con); } return result; } }