DBUtil

 public static Connection getConnection(){
     Connection con=null;
     try{
         con=DriverManager.getConnection(
           "jdbc:mysql://localhost:3306/department","root","root" 
       );
     }catch(Exception e){
         e.printStackTrace();
     }
     return con;
 }

 public static void release(ResultSet rs,Statement stmt,Connection con){
     if(rs!=null){
        try{rs.close();}catch(SQLException e){e.printStackTrace();};
     }
     if(stmt!=null){
        try{stmt.close();}catch(SQLException e){e.printStackTrace();};
     }
     if(con!= null){
        try{con.close();}catch(SQLException e){e.printStackTrace();};
     }
 }

 public boolean save(Department dept){
  Connection con = JDBC.getConnection();
  String sql = "insert into department values(?,?,?)";
  try {
   PreparedStatement pstmt = con.prepareStatement(sql);
   pstmt.setString(1, dept.getId());
   pstmt.setString(2, dept.getName());
   pstmt.setInt(3, dept.getNumber());
   pstmt.execute();
   System.out.println("保存成功");
   return true;
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
   System.out.println("保存失败");
   return false;
  }
 }
 
 public List<Department> getAllDept(String flag,String category){
  String sql = getDeptSql(flag,category);
  try {
   PreparedStatement pstmt = JDBC.getConnection().prepareStatement(sql);
   ResultSet rs = pstmt.executeQuery();
   List<Department> deptList = new ArrayList<Department>();
   while(rs.next()){
    Department dept = new Department();
    dept.setId(rs.getString(1));
    dept.setName(rs.getString(2));
    dept.setNumber(rs.getInt(3));
    deptList.add(dept);
   }
   System.out.println("查询成功");
   return deptList;
  } catch (Exception e) {
   e.printStackTrace();
   System.out.println("查询失败");
   return null;
  }
 }
 public String getDeptSql(String flag,String category){
  if(flag.equals("up")){
   if(category.equals("number")){
    return "select * from department order by number";
   }else{
    return "select * from department order by name";
   }
  }else{
   if(category.equals("number")){
    return "select * from department order by number desc";
   }else{
    return "select * from department order by name desc";
   }
  }
 }
 public static void main(String[] args) {
//  JDBC db = new JDBC();
 }
 
 

}