Research On Examination System Framework Based On Design Patterns And Its Application

Designing an exam system has certain degree of difficulty: At first, systematic business logic is changed constantly, there is characteristics in every discipline exam, and the exam type and content set theme the rule is also changed constantly , the system must adapt to these changes and fix these changes in the specific position of the system at least; Secondly, each development may use different exam pool of trying on, exam pool these may whom user leave over already, or a newly-built specific demand, so the system must offer a unanimous interface which visits the datum ;Finally, the systematic interface must be able to be very easy to change, in order to adapt to the users of the different levels, this kind of change must be under the prerequisite of influencing other parts of the system . Realize such an exam system, so need to structure a systematic framework .An online exam system framework based on the design patterns was introduced in the paper. At first, in the business entity layer, the factory method pattern and the builder pattern were adopted to control the variable work of creating a exam paper object, a strategic mode was adopted to control the generating of parameters and rules of the exam questions; Secondly, in the web layer, a interface between the Web layer and transaction-appearance layer was defined through the separation of question object's representation and data. Moreover, the facade pattern was adopted between the business facade layer and the Web layer. Finally, the entity-relation mapping problem in the data access layer was analyzed; Hence, a flexible and reusable exam system framework was obtained.In addition, the traditional test paper generating algorithm has the disadvantages of low speed, low success rate and low quality. This paper put forward a solution which can solve exam question group through improved hereditary algorithm. Adopt grouping real number code tactics at first, is it adjust probability of crossing and make a variation probability dynamically to come according to evolution situation of population then, adopt with right error adaptation degrees of function .It solve group rolls of characteristic of issue to ask to reflect to come, is it cross , make a variation and choose step to improve , confirm population's scale according to the actual conditions finally, change andtake the place of stopping judging . Experimental result indicate new group rolls of success rate of method disappear speed raise obviously, and has well overcome the ripe phenomenon of disappearing .It achieve a more satisfactory group effect.This paper realizes a common use network exam system based on exam systematic framework finally, and succeed in applying the improved hereditary algorithm to the design of a package of automatic group and realizing.