基于java的停车场管理系统

package com; import java.sql.*; public class DB { private String password; private Connection con; private String classname="com.microsoft.sqlserver.jdbc.SQLServerDriver"; private String url="jdbc:sqlserver://localhost:1433;DatabaseName=tingchechang"; public Connection getCon(){ try{ Class.forName(classname); con=DriverManager.getConnection(url,"sa","123"); } catch(Exception e){ e.printStackTrace(System.err); con=null; } return con; } public void closed(){ try{ if(con!=null)con.close(); } catch(Exception e){e.printStackTrace();} } //用于注册，添加 public int GetCount(String SQL){ try { Connection Con = getCon(); Statement Smt = Con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE); int counts = Smt.executeUpdate(SQL); return counts; } catch(SQLException e) { System.out.println("失败！"); return 0; } } //用于查询，登陆 public ResultSet GetRs(String SQL){ try { Connection Con = getCon(); Statement Smt = Con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE); ResultSet Rs = Smt.executeQuery(SQL); return Rs; } catch(SQLException e) { System.out.println("失败！"); return null; } } public String GetRsValue(String SQL){ try { Connection Con = getCon(); Statement Smt = Con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE); ResultSet Rs = Smt.executeQuery(SQL); System.out.println(Rs+"===========rs"); if(Rs.next()){ System.out.println("===========comein"); password=Rs.getString("password"); } System.out.println(password+"===========password"); return password; } catch(SQLException e) { System.out.println("失败！"); return null; } } //修改和删除 public boolean executeUpdate(String sql) { if (con == null) { getCon(); } try { Statement stmt = con.createStatement(); int iCount = stmt.executeUpdate(sql); System.out.println("操作成功，所影响的记录数为" + String.valueOf(iCount)); } catch (SQLException e) { System.out.println(e.getMessage()); System.out.println("executeUpdaterError!"); } return true; } }