Quick Start: Building a Web App by Spring Tool Suite





Small purple plants in springtime
There are some examples on spring.io to help developers to get started with using Spring.  While the official Quick Start guide demonstrates a simple way to generate "Hello World", it requires developers to choose their own favorite Integrated Developer Environment (IDE) or lightweight editor, and build the project by Maven at the command prompt.  Here is an alternative Quick Start guide that I have chosen the specific tools.

What to build
A classic "Hello World!" message replied to a web browser from Tomcat server.

What tools are required
Spring Tool Suite (version 4 in this example)
JDK (version 8 or above)
Note: Unlike the official Quick Start guide, installation of Spring Tool Suite but not Maven or Gradle is required.

Step 1
Install Spring Tool Suite, and launch it.

Step 2
Fill out the New Spring Starter Project form to generate the starter codes.
To launch the form: File > New > Spring Starter Project
Fill out the two pages of the form as below.

First page:


Notice that Gradle type is chosen for this example.
Change project Name, Group, Artifact, and Package to yours.

Second page:

In the "Available" text field, enter "Web" to search for the web-related components.
Select "Spring Web".
Click "Finish" to generate the codes.

Step 3:
On the navigation panel, locate the Java file "WebdemoApplication.java" and double-click to open it.

Modify the code by adding a hello method etc.:


Here is the code for copy-and-paste:
package com.calmalgo.spring.webdemo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
public class WebdemoApplication {

 public static void main(String[] args) {
  SpringApplication.run(WebdemoApplication.class, args);
 }

 @GetMapping("/hello")
 public String hello(@RequestParam(value = "name", defaultValue = "World") String name) {
  return String.format("Hello %s!", name);
 } 
  
}
Reminder: The package name should have been modified to yours.

Step 4
Run the application: Run > Run
That includes launching the Tomcat server.

Step 5:
At the same workstation, launch a web browser.
Go to address: localhost:8080/hello
The web browser will receive a reply of "Hello World!"


Additional step for experiment:

Modify the hello method to manipulate how to generate a reply to the browser.

Example 1:
@GetMapping("/hello")
public String hello(@RequestParam(value = "name", defaultValue = "World") String name) {  
    UnaryOperator<String> replyOp = n -> {
        return String.format("Hello %s", n);
    };    
    return replyOp.apply(name); 
}

Example 2:
@GetMapping("/morning")
public String morning(@RequestParam(value = "name", defaultValue = "World") String name) {  
    UnaryOperator<String> replyOp = n -> {
        return String.format("Good morning %s", n);
    };    
    return replyOp.apply(name); 
}



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