jsp的问题java.lang.NullPointerException
来源:百度知道 编辑:UC知道 时间:2024/07/05 08:43:53
我想要输入内容,然后保存下来。在写时,是分步调试的,正确。
把tomcat重启后,就不正确了 提示:
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:358)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
root cause
java.lang.NullPointerException
org.apache.jsp.ex29_jsp._jspService(ex29_jsp.java:74)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(
把tomcat重启后,就不正确了 提示:
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:358)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
root cause
java.lang.NullPointerException
org.apache.jsp.ex29_jsp._jspService(ex29_jsp.java:74)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(
1.问题出现在
String strcontent=request.getParameter("content");
当你第一次访问该页面时,你的请求地址中并没有content这个参数,所以调用java代码时,你的strcontent得到的值为空。
2.问题解决方案
(1)得到的strcontent有空判断,例如:pw.println(codetoString(strcontent).toString()); 这行可改为
pw.println(codetoString(strcontent==null?"":strcontent).toString());
<textarea name="content" id="content">er</textarea>
你在这个里面输入东西了没
<textarea>并非form组件,不能request,
String strcontent=request.getParameter("content");
并不能得到值
如要传值你可以用<input type="hidden" name="content" value="">
将<textarea name="content" id="content">er</textarea>
改为<textarea name="text" id="text">er</textarea>
用<Script language="javascript">
function getText(){
form1.content.value = text.innerHTML;
}
</script>
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