HTTP状态 500 -内部服务器错误

来源：2-12 自由编程

weixin_慕的地0390393

2022-10-14 20:05:07

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

public class SampleServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String number = req.getParameter(“n”);
int n = Integer.parseInt(number);
int add = 0;
for(int i = 1; i <= n;i++){
add += i;
}
PrintWriter out = resp.getWriter();
out.println(“累加和为:”+add);
}
}

<?xml version="1.0" encoding="UTF-8"?>

second
SecondServlet

second
/hi

sample
SampleServlet

sample
/sample

<?xml version="1.0" encoding="UTF-8"?>

4.0.0

<groupId>org.example</groupId>
<artifactId>SecondSerclet</artifactId>
<version>1.0-SNAPSHOT</version>

<dependencies>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
    </dependency>
</dependencies>

HTTP状态 500 -内部服务器错误
java.lang.NumberFormatException: null
java.lang.Integer.parseInt(Integer.java:542)
java.lang.Integer.parseInt(Integer.java:615)
SampleServlet.service(SampleServlet.java:12)
javax.servlet.http.HttpServlet.service(HttpServlet.java:765)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

写回答

1回答