java - Embed angular into spring application and access Spring Controllers when running ng serve

Question

I plan to set up a Spring-Angular application. I started right away with an Hello World-example to test out how to set up the environment. What I ended up doing:

Creating a Spring-Project and creating an Angular-application within this application. Now I can access Spring-REST-Controllers via the HttpClient Angular Module. (Code example see below).

The advantage: I can use mvn package to pack the Angular- and Spring-parts into one jar and simply deploy it on my tomcat. Sadly, when I run ng serve only the frontend is executed and I cannot access the data in my backend. Is there a way to set up my environment so that I can have the advantage of a one-project-solution and still use ng serve to test it out?

What I tried:

Pack the jar and execute it via terminal (java -jar %jar-file%) and using localhost:8080/hello as a path for my HttpClient instead of a simple /hello. That did not work out sadly.

The code I got so far:

app.component.ts

import { Component, OnInit } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit {
  title = 'HelloWorld';
  message: string;

  constructor(private http : HttpClient) {}

  ngOnInit() : void {
    //this is where I tried to use localhost:8080/hello instead
    this.http.get('/hello').subscribe( data => {
      console.log('DATA', data);
      this.message = data['message'];
    });
  }
}

Rest-Controller:

package com.example.helloWorld.controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;


@RestController
public class HelloWorldController {

    @GetMapping("/hello")
    public String sayHello() {
        return "{"message": "Hello, World!"}";
    }

}

pom.xml http://maven.apache.org/xsd/maven-4.0.0.xsd"> 4.0.0

<groupId>com.example</groupId>
<artifactId>helloWorld</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>helloWorld</name>
<description>Demo project for Spring Boot</description>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.0.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
</properties>

<dependencies>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.restdocs</groupId>
        <artifactId>spring-restdocs-mockmvc</artifactId>
        <scope>test</scope>
    </dependency>
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-autoconfigure</artifactId>
  <version>2.1.0.RELEASE</version>
  <type>jar</type>
 </dependency>
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
</dependencies>

<build>
    <plugins>
                    <plugin>
                        <groupId>org.codehaus.mojo</groupId>
                        <artifactId>exec-maven-plugin</artifactId>
                        <executions>
                            <execution>
                                <phase>validate</phase>
                                <goals>
                                    <goal>exec</goal>
                                </goals>
                            </execution>
                        </executions>
                        <configuration>
                            <executable>ng</executable>
                            <workingDirectory>src/main/ui</workingDirectory>
                            <arguments>
                                <argument>build</argument>
                            </arguments>
                        </configuration>
                    </plugin>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

Answer 1

To do like this

this.http.get('/hello').subscribe( data => {
      console.log('DATA', data);
      this.message = data['message'];
    });

You need to do some proxy configurations. Create one proxy-config.json file inside your project in the same directory where package.json is there.

{
    "/": {
        "target": "http://localhost:8080",
        "secure": false
    }
}

and in package.json inside scripts update "start" command with "start": "ng serve --proxy-config proxy-config.json", After that try npm start command to run your project.