【发布时间】：2014-09-27 18:40:35
【问题描述】：
请帮助解决以下问题。
我做了一个简单的 Spring MVC JSP 应用程序，中间我遇到了下面的空指针异常，但是当我重新运行应用程序或者有时它需要我的管理服务重新启动时，这个异常会被清除，请告知。
我只是试图从 jsp 提交我的登录表单并收到此错误。
java.lang.NullPointerException
at com.sun.faces.context.ApplicationMap.get(ApplicationMap.java:97)
at org.springframework.web.jsf.FacesContextUtils.getWebApplicationContext(FacesContextUtils.java:51)
at org.springframework.web.jsf.FacesContextUtils.getRequiredWebApplicationContext(FacesContextUtils.java:81)
at org.springframework.web.jsf.el.SpringBeanFacesELResolver.getWebApplicationContext(SpringBeanFacesELResolver.java:90)
at org.springframework.web.jsf.el.SpringBeanFacesELResolver.getBeanFactory(SpringBeanFacesELResolver.java:78)
at org.springframework.beans.factory.access.el.SpringBeanELResolver.getValue(SpringBeanELResolver.java:50)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at com.sun.faces.el.ChainTypeCompositeELResolver.getValue(ChainTypeCompositeELResolver.java:94)
at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:188)
at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:188)
at com.sun.el.parser.AstIdentifier.getValue(AstIdentifier.java:103)
at com.sun.el.parser.AstEmpty.getValue(AstEmpty.java:66)
at com.sun.el.parser.AstNot.getValue(AstNot.java:63)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:224)
at weblogic.servlet.jsp.ELHelper.evaluate(ELHelper.java:32)
at jsp_servlet._web_45_inf._jsp.__usertodolist._jspService(__usertodolist.java:175)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:34)
..........
UserToDoList_jsp.java 公共最终类 UserToDoList_jsp 扩展 org.apache.jasper.runtime.HttpJspBase 实现 org.apache.jasper.runtime.JspSourceDependent {
private static final JspFactory _jspxFactory = JspFactory.getDefaultFactory();
private static java.util.List<String> _jspx_dependants;
private org.apache.jasper.runtime.TagHandlerPool _jspx_tagPool_c_forEach_var_items;
private org.apache.jasper.runtime.TagHandlerPool _jspx_tagPool_form_select_tabindex_path_onchange;
private org.apache.jasper.runtime.TagHandlerPool _jspx_tagPool_c_set_value_target_property_nobody;
private org.apache.jasper.runtime.TagHandlerPool _jspx_tagPool_form_form_name_modelAttribute_method_action;
private org.apache.jasper.runtime.TagHandlerPool _jspx_tagPool_form_option_value_label_nobody;
private org.apache.jasper.runtime.TagHandlerPool _jspx_tagPool_c_if_test;
private org.apache.jasper.runtime.TagHandlerPool _jspx_tagPool_form_option_value_nobody;
private org.glassfish.jsp.api.ResourceInjector _jspx_resourceInjector;
public java.util.List<String> getDependants() {
return _jspx_dependants;
}
public void _jspInit() {
_jspx_tagPool_c_forEach_var_items = org.apache.jasper.runtime.TagHandlerPool.getTagHandlerPool(getServletConfig());
_jspx_tagPool_form_select_tabindex_path_onchange = org.apache.jasper.runtime.TagHandlerPool.getTagHandlerPool(getServletConfig());
_jspx_tagPool_c_set_value_target_property_nobody = org.apache.jasper.runtime.TagHandlerPool.getTagHandlerPool(getServletConfig());
_jspx_tagPool_form_form_name_modelAttribute_method_action = org.apache.jasper.runtime.TagHandlerPool.getTagHandlerPool(getServletConfig());
_jspx_tagPool_form_option_value_label_nobody = org.apache.jasper.runtime.TagHandlerPool.getTagHandlerPool(getServletConfig());
_jspx_tagPool_c_if_test = org.apache.jasper.runtime.TagHandlerPool.getTagHandlerPool(getServletConfig());
_jspx_tagPool_form_option_value_nobody = org.apache.jasper.runtime.TagHandlerPool.getTagHandlerPool(getServletConfig());
}
public void _jspDestroy() {
_jspx_tagPool_c_forEach_var_items.release();
_jspx_tagPool_form_select_tabindex_path_onchange.release();
_jspx_tagPool_c_set_value_target_property_nobody.release();
_jspx_tagPool_form_form_name_modelAttribute_method_action.release();
_jspx_tagPool_form_option_value_label_nobody.release();
_jspx_tagPool_c_if_test.release();
_jspx_tagPool_form_option_value_nobody.release();
}
public void _jspService(HttpServletRequest request, HttpServletResponse response)
throws java.io.IOException, ServletException {
PageContext pageContext = null;
HttpSession session = null;
ServletContext application = null;
ServletConfig config = null;
JspWriter out = null;
Object page = this;
JspWriter _jspx_out = null;
PageContext _jspx_page_context = null;
try {
response.setContentType("text/html;charset=UTF-8");
pageContext = _jspxFactory.getPageContext(this, request, response,
null, true, 8192, true);
_jspx_page_context = pageContext;
application = pageContext.getServletContext();
config = pageContext.getServletConfig();
session = pageContext.getSession();
out = pageContext.getOut();
_jspx_out = out;
_jspx_resourceInjector = (org.glassfish.jsp.api.ResourceInjector) application.getAttribute("com.sun.appserv.jsp.resource.injector");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("\n");
out.write("<!DOCTYPE html>\n");
out.write("<html>\n");
out.write(" <head>\n");
out.write(" <title>Home</title>\n");
out.write(" <div class=\"inset\">\n");
out.write(" ");
out.print(session.getAttribute("dateTime"));
out.write("\n");
out.write(" <h2> TO DO LIST </h2> \n");
out.write(" ");
out.print(session.getAttribute("user"));
out.write("\n");
out.write(" <!-- <link href=\"style.css\" rel=\"stylesheet\" type=\"text/css\"/>\n");
out.write(" -->\n");
out.write(" <script type=\"text/javascript\">\n");
out.write("\n");
out.write(" function changeFunc($i) {\n");
out.write(" alert($i \"Please select Approve or Reject\");\n");
out.write(" }\n");
out.write(" </script> \n");
out.write(" </head> \n");
out.write(" <body>\n");
out.write(" <form action=\"logout\" method=\"POST\">\n");
out.write(" <button type=\"submit\">Logout</button> \n");
out.write(" </form> \n");
out.write("\n");
out.write(" <form name=\"Add\" action=\"Adduser\" method=\"post\">\n");
out.write(" <button type=\"submit\">ADD</button> \n");
out.write("\n");
out.write(" </form>\n");
out.write(" <form name=\"Modify\" action=\"Modifyuser\" method=\"post\">\n");
out.write(" <button type=\"submit\">Modify</button> \n");
out.write("\n");
out.write(" </form>\n");
out.write(" ");
// form:form
org.springframework.web.servlet.tags.form.FormTag _jspx_th_form_form_0 = (org.springframework.web.servlet.tags.form.FormTag) _jspx_tagPool_form_form_name_modelAttribute_method_action.get(org.springframework.web.servlet.tags.form.FormTag.class);
_jspx_th_form_form_0.setPageContext(_jspx_page_context);
_jspx_th_form_form_0.setParent(null);
_jspx_th_form_form_0.setMethod("POST");
_jspx_th_form_form_0.setName("TransactionAction");
_jspx_th_form_form_0.setModelAttribute("action");
_jspx_th_form_form_0.setAction("transactionAction");
int[] _jspx_push_body_count_form_form_0 = new int[] { 0 };
try {
int _jspx_eval_form_form_0 = _jspx_th_form_form_0.doStartTag();
if (_jspx_eval_form_form_0 != javax.servlet.jsp.tagext.Tag.SKIP_BODY) {
do {
out.write("\n");
out.write(" ");
// c:if
org.apache.taglibs.standard.tag.rt.core.IfTag _jspx_th_c_if_0 = (org.apache.taglibs.standard.tag.rt.core.IfTag) _jspx_tagPool_c_if_test.get(org.apache.taglibs.standard.tag.rt.core.IfTag.class);
_jspx_th_c_if_0.setPageContext(_jspx_page_context);
_jspx_th_c_if_0.setParent((javax.servlet.jsp.tagext.Tag) _jspx_th_form_form_0);
_jspx_th_c_if_0.setTest(((java.lang.Boolean) org.apache.jasper.runtime.PageContextImpl.evaluateExpression("${not empty ToDoList}", java.lang.Boolean.class, (PageContext)_jspx_page_context, null)).booleanValue());
int _jspx_eval_c_if_0 = _jspx_th_c_if_0.doStartTag();
if (_jspx_eval_c_if_0 != javax.servlet.jsp.tagext.Tag.SKIP_BODY) {
do {
out.write("\n");
out.write("\n");
out.write(" <table>\n");
out.write("\n");
out.write(" <tr> <th>ID</th>\n");
out.write(" <th>LOGIN ID</th>\n");
out.write(" <th>MAKER</th>\n");
out.write(" <th>TRANSACTION TYPE</th>\n");
out.write(" <th>STATUS</th>\n");
out.write(" </tr> \n");
out.write(" ");
// c:forEach
org.apache.taglibs.standard.tag.rt.core.ForEachTag _jspx_th_c_forEach_0 = (org.apache.taglibs.standard.tag.rt.core.ForEachTag) _jspx_tagPool_c_forEach_var_items.get(org.apache.taglibs.standard.tag.rt.core.ForEachTag.class);
_jspx_th_c_forEach_0.setPageContext(_jspx_page_context);
_jspx_th_c_forEach_0.setParent((javax.servlet.jsp.tagext.Tag) _jspx_th_c_if_0);
_jspx_th_c_forEach_0.setVar("item");
_jspx_th_c_forEach_0.setItems((java.lang.Object) org.apache.jasper.runtime.PageContextImpl.evaluateExpression("${ToDoList}", java.lang.Object.class, (PageContext)_jspx_page_context, null));
int[] _jspx_push_body_count_c_forEach_0 = new int[] { 0 };
try {
int _jspx_eval_c_forEach_0 = _jspx_th_c_forEach_0.doStartTag();
if (_jspx_eval_c_forEach_0 != javax.servlet.jsp.tagext.Tag.SKIP_BODY) {
do {
out.write("\n");
out.write(" <tr>\n");
out.write(" <td> <input value=\"");
out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.evaluateExpression("${item[0]}", java.lang.String.class, (PageContext)_jspx_page_context, null));
out.write("\" type=\"number\" name=\"id\" readonly /></td>\n");
out.write(" <td> <input value=\"");
out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.evaluateExpression("${item[1]}", java.lang.String.class, (PageContext)_jspx_page_context, null));
out.write("\" type=\"text\" name=\"loginId\" readonly /></td>\n");
out.write(" <td> <input value=\"");
out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.evaluateExpression("${item[2]}", java.lang.String.class, (PageContext)_jspx_page_context, null));
out.write("\" type=\"text\" name=\"maker\" readonly /></td>\n");
out.write(" <td> <input value=\"");
out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.evaluateExpression("${item[3]}", java.lang.String.class, (PageContext)_jspx_page_context, null));
out.write("\" type=\"text\" name=\"transactionType\" readonly /></td>\n");
out.write(" <td> <input value=\"");
out.write((java.lang.String) org.apache.jasper.runtime.PageContextImpl.evaluateExpression("${item[4]}", java.lang.String.class, (PageContext)_jspx_page_context, null));
out.write("\" type=\"text\" name=\"status\" readonly /></td>\n");
out.write(" <td>\n");
out.write(" ");
// form:select
...
}
【问题讨论】：
-
你真的不应该像那样比较字符串。你应该改用
"success".equals(result)。 -
@Makoto 感谢您的建议，我已相应更改。请就间歇性 NPE 提出建议
标签： java spring jsp spring-mvc nullpointerexception