404 error on main controller when using spring boot - java

I m trying to do Spring MVC tutorial:
It makes you create a main controller ad start a SpringApplication.
When I run the SpringApplication, I can see that a Tomcat server gets started, a controller class gets instanced as it should.
However, the mapping seems to fail : #RequestMapping("/greeting")
When I try to browse http://localhost:8080/TestSpringOpenEMM2/greeting
or http://localhost:8080/TestSpringOpenEMM2/greeting , I always get a 404 error.
(TestSpringOpenEMM2 is my project name).
I use eclipse IDE.
Here are my files:
package application;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class Application {
public static void main(String[] args) {
System.out.println("App starting" );
SpringApplication.run(Application.class, args);
System.out.println("App started" );
}
}
controller:
import javax.servlet.annotation.WebServlet;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
#Controller
public class GreetingController {
static{
System.out.println("Static init GreetingController");
}
#RequestMapping("/greeting")
public String greeting(#RequestParam(value="name", required=false, defaultValue="World") String name, Model model) {
System.out.println("starting servlet (greeting)");
model.addAttribute("name", name);
return "greeting";
}
public GreetingController(){
super();
System.out.println("new GreetingController");
}
}
pom:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>TestSpringOpenEMM2</groupId>
<artifactId>TestSpringOpenEMM2</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<build>
<sourceDirectory>src</sourceDirectory>
<plugins>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>2.6</version>
<configuration>
<warSourceDirectory>WebContent</warSourceDirectory>
<failOnMissingWebXml>false</failOnMissingWebXml>
</configuration>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.3</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot</artifactId>
<version>1.2.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-autoconfigure</artifactId>
<version>1.2.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>4.1.7.RELEASE</version>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-logging-juli</artifactId>
<version>8.0.23</version>
</dependency>
</dependencies>
</project>

Maybe you can use #RestController not #Controller. For REST api, if I use #Controller, the request will cause a 404 not found error, but after I change it to #RestController, the request works fine.

If you raise the Spring log level it should, when web-app starts, show you which URLs are being mapped to which classes/methods. That may help.
Also, if you're using Eclipse, right click project -> Properties -> Web Project Settings -> Context root. Make sure it is as you expect it to be i.e. TestSpringOpenEMM2. I have seen plenty of examples of this (context root) not being as expected in Eclipse.

The spring-boot-starter-parent is a great way to use Spring Boot, hence use a pom.xml like this:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>TestSpringOpenEMM2</groupId>
<artifactId>TestSpringOpenEMM2</artifactId>
<version>0.0.1-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.2.5.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
</project>
By default spring boot using a embedded tomcat container, you just need to run the main method. Read more on this topic on Spring Boot's Doc

Related

Sping RestController not responding to request

I am just trying to implement a sample rest controller on spring boot for learning. When i am sending the request through web browser i am getting a white label error.
My applications context path is set to /learn. Below are my source files, project structure and pom.xml.
TestController.java
package com.practice.learn.controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
#RestController
#RequestMapping("/learn")
public class TestController {
TestController(){
System.out.println("TestController initialized");
}
#GetMapping("/test")
public String testMethod() {
System.out.println("Inside test method");
return "This is sample text";
}
}
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.7.8</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<groupId>com.practice</groupId>
<artifactId>learn</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>learn</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>11</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
LearnApplication.java
package com.practice.learn;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class LearnApplication {
public static void main(String[] args) {
SpringApplication.run(LearnApplication.class, args);
}
}
application.properties
server.port=8081
server.servlet.context-path=/learn
since you already set the servlet context path as '/learn' in your configuration file, you do not need to add '/learn' again in the RequestMapping in your controller. just remove it and let us know.

If I add spring-boot-starter-data-jpa to a simple spring application I get 404s but none if it's not there

I am trying to debug why a my application won't show, and in doing so I have this small application running hello world. This does work, it shows the text on the screen, great. But then if I add spring-boot-starter-data-jpa to the pom file, I get a 404 error instead. I need to use spring-boot-starter-data-jpa and have no idea why it doesn't work as expected.
pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>spring-boot-hello</artifactId>
<packaging>war</packaging>
<name>Spring Boot Hello World Example</name>
<version>1.0</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.5.5</version>
</parent>
<properties>
<java.version>11</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- <dependency>-->
<!-- <groupId>org.springframework.boot</groupId>-->
<!-- <artifactId>spring-boot-starter-tomcat</artifactId>-->
<!-- <scope>provided</scope>-->
<!-- </dependency>-->
<!--this is the issued one-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
</dependencies>
<build>
<finalName>testapp</finalName>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
controller
package org.example;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
#RestController
public class HelloController {
#RequestMapping("/")
String hello() {
return "Hello World, Spring Boot!";
}
}
main class
package org.example;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
#SpringBootApplication
public class MyWebApplication extends SpringBootServletInitializer {
public static void main(String[] args) {
SpringApplication.run(MyWebApplication.class, args);
}
#Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder builder){
return builder.sources(MyWebApplication.class);
}
}
I have gone through every other answer I could find and made sure I was using restcontroller instead of controller, I believe my main class is in the correct spot, I am at a loss as to why one dependency, especially one that isn't being used yet, causes a 404.
In application.properties file in resource folder did you set database configuration such asusername, password and url? It should be set like this.
spring.datasource.url=jdbc:mysql://localhost:3306/restapi
spring.datasource.username=root
spring.datasource.password=
And it's better to use #GetMapping annotation instead of #RequestMapping.

Spring Boot - Deployable War - ClassNotFoundException

I have been attempting to create a spring boot deployable war so that it can be deployed to a tomcat server (I would like to note that it runs fine as an executable jar). However, I have been running into the following exception which occurs on my Tomcat 9 server (I have one running within IntelliJ and another one running on a linux server, both throw the same exception):
org.springframework.beans.factory.BeanDefinitionStoreException: Failed to process import candidates for configuration class [com.example.demo.DemoApplication]; nested exception is java.lang.NoClassDefFoundError: org/springframework/context/annotation/AdviceMode
From my understanding, this lives in the spring-context jar, which is correctly being pulled into the build via maven. I created a super simple demo app with spring boot and I really can't see why I would be running into this issue.
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.4.4</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>11</java.version>
<start-class>com.example.demo.DemoApplication</start-class>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>5.3.5</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.3.5</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<excludes>
<exclude>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</exclude>
</excludes>
</configuration>
</plugin>
</plugins>
</build>
</project>
And here is the main application file:
DemoApplication.java
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
#SpringBootApplication
#RestController
public class DemoApplication extends SpringBootServletInitializer {
#Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application.sources(DemoApplication.class);
}
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
#RequestMapping(value = "/")
public String hello() {
return "Hello World from Tomcat";
}
}
I am at a total loss as to why I'm hitting this ClassNotFoundException. Looking at the war file, I do see all the appropriate libraries in the WEB-INF/lib folder. The two files I pasted above are literally all the project I'm attempting to run is.
I have looked at this guide: Spring Boot Traditional Deployment
If I remove extends SpringBootServletInitializer, then the error goes away, but then I of course don't really have a functional spring boot war file.
did you import spring-boot-starter-web? This class is located in context lib that is imported by spring-boot-starter-web
Well, apparently I had a lib in my Tomcat lib folder that was built to include ALL dependent libraries... which happens to have a spring dependency... so it was pulling in an older version of spring, which was causing a conflict. With the jar swapped out with one that doesn't include all dependencies, it loaded.

Spring Boot application can't be reached from browser nor Postman

I have a simple Spring Boot application that serves some static resources when accessed from localhost:8899.
I installed tomcat on my pc and tried to deploy the war file, but it kept giving me a 404 response. Next, I wanted to modify some things in the spring boot app, but now if I start up the app, I can't reach it.
I also tried to use Postman to see if at least the rest controller is working, but I get the "There was an error connecting to localhost:8899" message.
I ended up uninstalling the tomcat service, I also uninstalled tomcat and reverted to a previous commit on the application, which was working before, but I get the same result. The app starts up at port 8899 without errors, but I can't get any response neither by accessing the static resources from the browser nor from sending a request from Postman to the rest controller.
I have no clue what to look for because I get no errors other than what you can see in the screenshot.
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>todoey-backend</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<name>todoey-backend</name>
<description>Reminder application</description>
<properties>
<java.version>1.10</java.version>
</properties>
<parent>
<groupId>org.reminder</groupId>
<artifactId>todoey-parent</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-commons</artifactId>
<version>2.2.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-mail</artifactId>
<version>2.2.5.RELEASE</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>10</source>
<target>10</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
application.properties
server.port=8899
# DB
spring.datasource.url=jdbc:h2:file:./todoey-be/src/main/resources/db/todoey_db
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=password
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.jpa.hibernate.ddl-auto=update
ReminderController.java
package com.reminder.todoey.controller;
import com.reminder.todoey.model.Reminder;
import com.reminder.todoey.service.ReminderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import java.util.List;
#RestController
#RequestMapping("reminder")
public class ReminderController {
#Autowired
private ReminderService reminderService;
#GetMapping
public ResponseEntity<List<Reminder>> getAllReminders() {
List<Reminder> reminderList = reminderService.getAllReminders();
return ResponseEntity.ok(reminderList);
}
#PostMapping
public ResponseEntity writeReminder(#RequestBody final Reminder reminder) {
reminderService.saveReminder(reminder);
return ResponseEntity.status(HttpStatus.OK).build();
}
#DeleteMapping
public ResponseEntity deleteReminder(#RequestParam final long id) {
reminderService.deleteReminder(id);
return ResponseEntity.status(HttpStatus.OK).build();
}
#PutMapping
public ResponseEntity updateReminder(#RequestBody final Reminder reminder) {
reminderService.updateReminder(reminder);
return ResponseEntity.status(HttpStatus.OK).build();
}
#PutMapping(path = "/email-address")
public ResponseEntity updateEmailAddress(#RequestParam final String email) {
reminderService.updateEmailAddress(email);
return ResponseEntity.status(HttpStatus.OK).build();
}
#GetMapping(path = "/email-address")
public ResponseEntity<String> getEmailAddress() {
return ResponseEntity.ok(reminderService.getEmailAddress());
}
}
I managed to figure out why I couldn't reach my application. I had an async method with and infinite loop that was checking the time to see when to send the reminders. This method was annotated with both #Async and #PostConstruct because I wanted it to be called as soon as the application starts. After deleting #PostConstruct, everything worked just fine.

Spring Boot Hello World Example Not working

I have downloaded spring boot example from https://start.spring.io/.
I tried many times but i get same error again and again:
Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication
at com.example.demo.Application.main(Application.java:10)
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
Here is my pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>SpringBoot</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<name>SpringBoot</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
and SpringBootClass
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
also my ControllerClass
package com.example.demo.controller;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
#RestController
#EnableAutoConfiguration
public class HelloWorldController {
#RequestMapping("/hello")
#ResponseBody
public String sayHello() {
return "Hello World Developer!!!";
}
}
I am struggling from past three days and not getting any help from anywhere.
I am using Spring Tool Suite
I am new to Spring Boot and need help here
Set Maven to you path and try from command prompt/ terminal with command:
mvn clean install
this will create jar file in target folder.
go to target folder and run java -jar jarName.jar.
OR
Try cleaning the project from project tab,
Add all the maven dependencies to eclipse build path.
Then try running it as java application.
It is caused by a corrupt Maven repository.
Delete everything under C:\Users\<me>\.m2\repository.
Then do Eclipse Maven Update, and it will work.
it is like spring-boot.jar got corrupted.

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