http status 500 - string index out of range: -10

type exception report\r

message string index out of range: -10\r

description the server encountered an internal error that prevented it from fulfilling this request.\r

exception

java.lang.stringindexoutofboundsexception: string index out of range: -10

java.lang.string.substring(string.java:1911)

.lib.decryptutil.filedecrypt(decryptutil.java:22)

.encrypt.action.execute(action.java:59)

sun.reflect.generatedmethodaccessor38.comvoke(unknoethodaccessorimpl.comvoke(delega挺methodaccessorimpl.java:43)

java.lang.reflect.method.comvoke(method.java:606)

.opensymphony.xinvocation.comvokeaction(defaultactioninvocation.java:452)

.opensymphony.xinvocation.comvokeactiononly(defaultactioninvocation.java:291)

.opensymphony.xinvocation.comvoke(defaultactioninvocation.java:254)

.opensymphony.xterceptor.dointercept(defaultphony.xterceptor.comtercept(methodfilterinterceptor.java:98)

.opensymphony.xinvocation.comvoke(defaultactioninvocation.java:248)

.opensymphony.xinterceptor.dointercept(validationinterceptor.java:263)

.apache.struts2.comterceptor.validation.annotationvalidationinterceptor.dointercept(annotationvalidationinterceptor.java:68)

.opensymphony.xterceptor.comtercept(methodfilterinterceptor.java:98)

.opensymphony.xinvocation.comvoke(defaultactioninvocation.java:248)

.opensymphony.xversionerrorinterceptor.comtercept(conversionerrorinterceptor.java:133)

.opensymphony.xinvocation.comvoke(defaultactioninvocation.java:248)

.opensymphony.xterceptor.dointercept(parametersinterceptor.java:207)

.opensymphony.xterceptor.comtercept(methodfilterinterceptor.java:98)

.opensymphony.xinvocation.comvoke(defaultactioninvocation.java:248)

.opensymph