增加一个空指针的判断，在值传错的情况下会有这种情况

servers/boe-server-all/src/main/java/com/xboe/module/exam/service/impl/ExamTestServiceImpl.java

@@ -58,6 +58,9 @@ public class ExamTestServiceImpl implements IExamTestService {
     @Override
     public ExamTest detail(String id) {
         ExamTest examTest = examTestDao.get(id);
+        if(examTest==null) {
+        	return null;
+        }
         Object field = examPaperDao.findField("testName", FieldFilters.eq("id", examTest.getPaperId()));
         if(field!=null){
             examTest.setPaperName((String) field);