Jednostavan "Hello World" Tomcat servlet za testiranje performansi

Korak 1: Postavite strukturu projekta

MyJsonServlet/
├── src/
│   └── com/
│       └── example/
│           └── JsonStatusServlet.java
├── web/
│   ├── WEB-INF/
│   │   └── web.xml
│   └── index.html (opcionalno)
└── build.gradle ili pom.xml (za upravljanje ovisnostima)

Korak 2: Kreirajte klasu servleta

package com.example;

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

@WebServlet("/status")  // Ova anotacija mapira servlet na URL /status
public class JsonStatusServlet extends HttpServlet {
    
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        // Postavite tip sadržaja odgovora na JSON
        response.setContentType("application/json");
        response.setCharacterEncoding("UTF-8");
        
        // Kreirajte JSON odgovor
        String jsonResponse = "{\"status\": \"OK\", \"message\": \"Server radi\", \"timestamp\": " + 
                             System.currentTimeMillis() + "}";
        
        // Napišite JSON odgovor
        PrintWriter out = response.getWriter();
        out.print(jsonResponse);
        out.flush();
    }
}

Korak 3: Konfigurirajte web.xml (Alternativa anotaciji)

Ako ne koristite anotaciju @WebServlet, kreirajte/izmijenite WEB-INF/web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
                             http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    
    <servlet>
        <servlet-name>JsonStatusServlet</servlet-name>
        <servlet-class>com.example.JsonStatusServlet</servlet-class>
    </servlet>
    
    <servlet-mapping>
        <servlet-name>JsonStatusServlet</servlet-name>
        <url-pattern>/status</url-pattern>
    </servlet-mapping>
    
</web-app>

Korak 4: Izgradnja i implementacija

Korištenje Mavena:

1. Dodajte ovo u vaš pom.xml:

<dependencies>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
        <scope>provided</scope>
    </dependency>
</dependencies>

2. Izgradite s mvn package i implementirajte WAR datoteku u Tomcatov direktorij webapps

Ručno:

1. Kompajlirajte servlet:

javac -cp "/putanja/do/tomcat/lib/servlet-api.jar" src/com/example/JsonStatusServlet.java -d WEB-INF/classes

2. Kreirajte WAR datoteku:

jar cvf MyJsonServlet.war *

3. Kopirajte WAR datoteku u Tomcatov direktorij webapps

Korak 5: Testirajte servlet

Pokrenite Tomcat i posjetite:

http://localhost:8080/MyJsonServlet/status

Trebali biste vidjeti JSON odgovor:

{
    "status": "OK",
    "message": "Server radi",
    "timestamp": 1620000000000
}