javaee通讯录系统

package chelian.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.List; public class JDBCUtil { private static final String Url = "jdbc:mysql://localhost:3306/db_address?characterEncoding=UTF-8"; private static final String User = "root"; private static final String Password = "12344"; private static final String Driver = "com.mysql.jdbc.Driver"; private static Connection con = null; private static PreparedStatement ps = null; private static ResultSet rs = null; public static int IDentity;// 新增操作时的id static { try { Class.forName(Driver);// 注册驱动 } catch (ClassNotFoundException e) { throw new ExceptionInInitializerError(e); } } public static Connection getConnection() throws SQLException { return DriverManager.getConnection(Url, User, Password); } /** * 更新或者保存数据 * * @param sql * @return */ public static boolean updateOrSave(String sqlStr, List<Object> values) { System.out.println("JDBCUtil SQL: " + sqlStr); try { con = getConnection(); ps = con.prepareStatement(sqlStr); int size = values.size(); for (int i = 0; i < size; i++) { ps.setObject((i + 1), values.get(i)); } int result = ps.executeUpdate(); ps = con.prepareStatement("select @@identity"); rs = ps.executeQuery(); if (rs.next()) { JDBCUtil.IDentity = (Integer) rs.getInt(1); } return result > 0 ? true : false; } catch (Exception e) { e.printStackTrace(); } finally { free(rs, ps, con); } return false; } public static boolean delete(String sqlStr, int id) { System.out.println("JDBCUtil SQL: " + sqlStr); try { con = getConnection(); ps = con.prepareStatement(sqlStr); ps.setInt(1, id); int result = ps.executeUpdate(); return result > 0 ? true : false; } catch (Exception e) { e.printStackTrace(); } finally { free(null, ps, con); } return false; } /** * 释放数据库的连接等资源 * * @param rs * @param ps * @param conn */ public static void free(ResultSet rs, PreparedStatement ps, Connection conn) { try { if (rs != null) { rs.close(); } } catch (SQLException e) { e.printStackTrace(); } finally { try { if (ps != null) { ps.close(); } } catch (SQLException e) { e.printStackTrace(); } finally { if (conn != null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } } } /** * 这个函数查询出来的将查出来的所有列的值放在list里面 每一条list记录有很多Object,用数组存储 * * @param sqlStr * @param values * 参数值 * @return */ public static List<Object[]> queryObjectList(String sqlStr, List<Object> values) { System.out.println("JDBCUtil SQL: " + sqlStr); List<Object[]> objs = new ArrayList<Object[]>(); try { con = getConnection(); ps = con.prepareStatement(sqlStr); int size = values.size(); for (int i = 0; i < size; i++) { ps.setObject((i + 1), values.get(i)); } rs = ps.executeQuery(); ResultSetMetaData rsd = null; while (rs.next()) { rsd = rs.getMetaData(); int cols = rsd.getColumnCount();// 所有列数 Object[] obj = new Object[cols]; for (int i = 0; i < cols; i++) { obj[i] = rs.getObject(i + 1); } objs.add(obj); } } catch (Exception e) { e.printStackTrace(); } finally { free(rs, ps, con); } return objs; } /** * 这个函数查询出来的将查出来的所有列的值放在list里面 每一条list记录有很多Object,用数组存储 * * @param sqlStr * @param value 一个参数 * @return */ public static List<Object[]> queryObjectList(String sqlStr, Object value) { List<Object> values = new ArrayList<Object>(); values.add(value); return queryObjectList(sqlStr, values); } /** * 这个函数查询出来的将查出来的所有列的值放在list里面 每一条list记录有很多Object,用数组存储 * * @param sqlStr * @return */ public static List<Object[]> queryObjectList(String sqlStr) { List<Object> values = new ArrayList<Object>(); return queryObjectList(sqlStr, values); } /** * 查询一个对象，而这个对象的所有属性值存放在数组中 * * @param sqlStr * @param values 参数值 * @return */ public static Object[] queryObject(String sqlStr, List<Object> values) { System.out.println("JDBCUtil SQL: " + sqlStr); Object[] objs = null; try { con = getConnection(); ps = con.prepareStatement(sqlStr); int size = values.size(); for (int i = 0; i < size; i++) { ps.setObject((i + 1), values.get(i)); } rs = ps.executeQuery(); ResultSetMetaData rsd = null; if (rs.next()) { rsd = rs.getMetaData(); int cols = rsd.getColumnCount();// 所有列数 objs = new Object[cols]; for (int i = 0; i < cols; i++) { objs[i] = rs.getObject(i + 1); } } } catch (Exception e) { e.printStackTrace(); } finally { free(rs, ps, con); } return objs; } /** * 查询一个对象，而这个对象的所有属性值存放在数组中 * * @param sqlStr * @param value 一个参数值 * @return */ public static Object[] queryObject(String sqlStr, Object value) { List<Object> values = new ArrayList<Object>(); values.add(value); return queryObject(sqlStr, values); } /** * 查询一个对象，而这个对象的所有属性值存放在数组中 * * @param sqlStr * @return */ public static Object[] queryObject(String sqlStr) { List<Object> values = new ArrayList<Object>(); return queryObject(sqlStr, values); } /* public static void main(String[] args) { List<Object[]> list = queryObjectList("select * from user", new ArrayList<Object>()); //List<Object[]> list = queryObjectList("select u.*, q.name from user u, question q where q.userId=u.id", new ArrayList<Object>()); for (Object[] o : list) { for (Object oo : o) { System.out.print(oo); } System.out.println(); } }*/ }