英文:
Status 500 error instantiating servlet class in Tomcat
问题
I was executing a web project and it is throwing an error 500 error instatiating servlet class .
我正在执行一个Web项目，但它抛出了一个错误500错误，实例化Servlet类。
I am using tomcat 9.0.71 and using web module 4.0 .
我使用的是Tomcat 9.0.71，并且使用Web模块4.0。
This is the error message on the screen.
这是屏幕上的错误消息。
This is the error page status 500
This is the html document
这是HTML文档
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>This is a hello world</h1>
<br>
<form action="hello" method="get">
<input type="submit">click to say hello world
</form>
</body>
</html>
This is the servlet class
这是Servlet类
package ronit;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.*;
@WebServlet("/hello")
class hello extends HttpServlet{
static final long serialVersionUID = 35335L;
public void doGet(HttpServletRequest req, HttpServletResponse res) {
try {
PrintWriter p = res.getWriter();
p.println("Hello World");
}catch(IOException e) {e.printStackTrace();}
}}
This is the deployment configuration in the server
这是服务器中的部署配置
This is the console after execution
This is the project explorer view
I am using annotations instead of web.xml and deploying the file by right clicking on the project and run on server .
我使用注解而不是web.xml，并通过右键单击项目并在服务器上运行来部署文件。
Please consider telling me if more details required on question
如果需要更多细节，请告诉我。
英文:
I was executing a web project and it is throwing an error 500 error instatiating servlet class .
I am using tomcat 9.0.71 and using web module 4.0 .
This is the error message on the screen.
This is the error page status 500
This is the html document
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>This is a hello world</h1>
<br>
<form action ="hello" method="get">
<input type="submit">click to say hello world
</form>
</body>
</html>
This is the servlet class
package ronit;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.*;
@WebServlet("/hello")
class hello extends HttpServlet{
static final long serialVersionUID = 35335L;
public void doGet(HttpServletRequest req, HttpServletResponse res) {
try {
PrintWriter p = res.getWriter();
p.println("Hello World");
}catch(IOException e) {e.printStackTrace();}
}}
This is the deployment configuration in the server
This is the console after execution
This is the project explorer view
I am using annotations instead of web.xml and deploying the file by right clicking on the project and run on server .
Please consider telling me if more details required on question
答案1
得分: 0
Your servlet class has no public, zero argument, constructor. It needs one, otherwise Tomcat can not instantiate it--exactly as the error output is telling you.
英文:
Your servlet class has no public, zero argument, constructor. It needs one, otherwise Tomcat can not instantiate it--exactly as the error output is telling you.
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