Add connection between spring boot server and postgresql database

Signed-off-by: Guillaume Lours <guillaume.lours@docker.com>

samples/spring-postgres/backend/pom.xml

@@ -37,6 +37,15 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-jersey</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.postgresql</groupId>
+            <artifactId>postgresql</artifactId>
+            <scope>runtime</scope>
+        </dependency>
         <dependency>
             <groupId>org.springframework.session</groupId>
             <artifactId>spring-session-core</artifactId>

samples/spring-postgres/backend/src/main/java/com/company/project/controllers/HomeController.java

@@ -1,5 +1,8 @@
 package com.company.project.controllers;
 
+import com.company.project.entity.Greeting;
+import com.company.project.repository.GreetingRepository;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -7,8 +10,13 @@ import org.springframework.web.bind.annotation.GetMapping;
 @Controller
 public class HomeController {
 
+    @Autowired
+    private GreetingRepository repository;
+
     @GetMapping("/")
     public String showHome(String name, Model model) {
+        Greeting dockerGreeting = repository.findById(1).orElse(new Greeting("Not Found 😕"));
+        model = model.addAttribute("name", dockerGreeting.getName());
         return "home";
     }
 

samples/spring-postgres/backend/src/main/java/com/company/project/entity/Greeting.java

@@ -0,0 +1,57 @@
+package com.company.project.entity;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "GREETINGS")
+public class Greeting {
+
+    @Id
+    private int id;
+    private String name;
+
+    public Greeting() {
+    }
+
+    public Greeting(String name) {
+        this.name = name;
+    }
+
+    public Greeting(int id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Greeting greeting = (Greeting) o;
+
+        return name.equals(greeting.name);
+    }
+
+    @Override
+    public int hashCode() {
+        return name.hashCode();
+    }
+}

samples/spring-postgres/backend/src/main/java/com/company/project/repository/GreetingRepository.java

@@ -0,0 +1,9 @@
+package com.company.project.repository;
+
+import com.company.project.entity.Greeting;
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface GreetingRepository extends CrudRepository<Greeting, Integer> {
+}

samples/spring-postgres/backend/src/main/resources/application.properties

@@ -1 +1,11 @@
+spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.PostgreSQLDialect
+spring.jpa.hibernate.ddl-auto=none
+spring.jpa.hibernate.show-sql=true
 
+spring.datasource.url=jdbc:postgresql://db:5432/${POSTGRES_DB}
+spring.datasource.username=postgres
+spring.datasource.password=${POSTGRES_PASSWORD:db-wrz2z}
+spring.datasource.initialization-mode=always
+spring.datasource.initialize=true
+spring.datasource.schema=classpath:/schema.sql
+spring.datasource.continue-on-error=true

samples/spring-postgres/backend/src/main/resources/data.sql

@@ -0,0 +1 @@
+INSERT INTO GREETINGS(name) values ('Docker');

samples/spring-postgres/backend/src/main/resources/schema.sql

@@ -0,0 +1,4 @@
+CREATE TABLE IF NOT EXISTS GREETINGS (
+    id serial PRIMARY KEY,
+    name varchar(50) NOT NULL
+);

samples/spring-postgres/backend/src/main/resources/templates/home.ftlh

@@ -5,5 +5,5 @@
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
 </head>
 <body>
-	<p>Hello from Docker!</p>
+	<p>Hello from ${name}!</p>
 </body>

samples/spring-postgres/docker-compose.yaml

@@ -4,6 +4,10 @@ services:
     build: backend
     ports:
     - 80:8080
+    environment:
+      POSTGRES_DB: example
+    networks:
+      - spring-postges
   db:
     environment:
       POSTGRES_DB: example
@@ -14,8 +18,12 @@ services:
     - db-password
     volumes:
     - db-data:/var/lib/postgresql/data
+    networks:
+      - spring-postges
 volumes:
   db-data: {}
 secrets:
   db-password:
     file: db/password.txt
+networks:
+  spring-postges: {}