視屏里面校驗的時候，那個空指針異常，如何消除？java.lang.NullPointerException?? ?at java.util.ComparableTimSort.countRunAndMakeAscending(ComparableTimSort.java:316)?? ?at java.util.ComparableTimSort.sort(ComparableTimSort.java:184)?? ?at java.util.Arrays.sort(Arrays.java:1246)?? ?at com.utility.yongfeim.CheckUtil.checkSignature(CheckUtil.java:12)?? ?at com.myservlet.yongfeim.WeixinSerlet.doGet(WeixinSerlet.java:31)?? ?at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)?? ?at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)