Make a request and display the result on the screen (thymeleaf)

** (Goal) Embed the POST value (first and last name) in the html form and display it on the screen **

Project Root
└─src
    └─ main
        └─ java  
            └─ com.example
                └─ demo
                    └─trySpring
                       └─HelloController.java

Project Root
└─src
    └─ main
        └─ resources
            └─templates
                 └─hello.html                 
                 └─helloResponse.html

Screen transition to hello.html with GET

Create input form

`hello.html`


<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org" lang="en">
<head>
    <meta charset="UTF-8">
    <title>Hello World</title>
</head>
<body>
    <h1>Hello World</h1>
    <form method="post" action="/hello">
Last name:
        <input type="text" name="text1" th:value="${text1_value}"/>
        <br>
name:
        <input type="text" name="text2" th:value="${text2_value}"/>
        <br><br>
        <input type="submit" value="click"/>
        <br>
    </form>
</body>
</html>

Create controller class (HelloController) to POST

Use model.addAttribute to connect and pass to the placeholder of the POST destination as a single character string.
GET / POST is OK with the same endpoint (URL)
If you check on the devtool network, you can see that a GET / POST request is being thrown.

`HelloController.java`


import lombok.Getter;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;

@Controller
public class HelloController {
    @GetMapping("/hello")
    private String getHello() {
        return "hello";
    }
    @PostMapping("/hello")
    public String postRequest(@RequestParam("text1")String text1,@RequestParam("text2")String text2, Model model){
        //Register the character string received from the HTML screen in Model
        model.addAttribute("userName","I"+ text1 +" "+ text2+"is."); 
        return "helloResponse"; //helloResponse.Screen transition to html
    }
}

Create helloResponse.html of POST destination

Returns the result of merging the template and model values (entered first and last name)

`helloResponse.html`


<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF8"></meta>
    <title>Response Sample</title>
</head>
<body>
<h1>Hello Response</h1>
<!--
Receives the value from Model and displays the received characters
The value specified in the placeholder(userName)Put in
-->
<p th:text="${userName}"></p><body>
</html>