BAEL-1980 Access an in-memory h2 db from 2 Spring Boot applications (#5230)

* Added Spring-Boot-H2 project

* Optimized imports and formatted code

* Code Formatting changes

* Renamed the client applicaiton

* Removed Name from pom.xml

* formatting changes - applied formatting style

* added souts

* Update SpringBootApp.java

* Update ClientSpringBootApp.java

* Fixed Formatting issues

* Fixed formatting and spelling mistakes

* added H2 shared db example

* a

* patch

* test

* Revert "Fixed formatting and spelling mistakes"

This reverts commit ed56ededec.

* Revert "test"

This reverts commit 4a7133dbd1.

* Revert "patch"

This reverts commit 404b9ebe74.

* Revert "a"

This reverts commit af77f84111.

* Revert "added H2 shared db example"

This reverts commit e16918cae3.

* Updated to have client and server in same directory

* Deleted old files

* removed unwanted directory

* formating

* removed unwanted module

* commentted removed module

* Revert "commentted removed module"

This reverts commit 211ff1441f.

* Revert "removed unwanted module"

This reverts commit 657f9ee45e.

* fixed pom.xml issue

* typo fixed

* fixed multiple main class issue

spring-boot-h2/spring-boot-h2-database/pom.xml

@@ -22,6 +22,8 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <java.version>1.8</java.version>
+        <!-- The main class to start by executing java -jar -->
+        <start-class>com.mycorp.starter.HelloWorldApplication</start-class>
     </properties>
 
     <dependencies>

spring-boot-h2/spring-boot-h2-database/src/main/java/com/baeldung/h2db/demo/client/ClientSpringBootApp.java

@@ -0,0 +1,53 @@
+package com.baeldung.h2db.demo.client;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.Arrays;
+import javax.annotation.PostConstruct;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.PropertySource;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.jdbc.core.RowMapper;
+
+@SpringBootApplication
+@ComponentScan("com.baeldung.h2db.demo.client")
+public class ClientSpringBootApp {
+
+    @Autowired
+    private JdbcTemplate jdbcTemplate;
+
+    public static void main(String[] args) {
+        System.setProperty("spring.datasource.url","jdbc:h2:tcp://localhost:9091/mem:mydb");
+        SpringApplication.run(ClientSpringBootApp.class, args);
+    }
+
+    @PostConstruct
+    private void initDb() {
+        System.out.println("****** Inserting more sample data in the table: Employees ******");
+        String sqlStatements[] = {
+            "insert into employees(first_name, last_name) values('Donald','Trump')",
+            "insert into employees(first_name, last_name) values('Barack','Obama')"
+        };
+
+        Arrays.asList(sqlStatements).stream().forEach(sql -> {
+            System.out.println(sql);
+            jdbcTemplate.execute(sql);
+        });
+
+        System.out.println(String.format("****** Fetching from table: %s ******", "Employees"));
+        jdbcTemplate.query("select id,first_name,last_name from employees",
+            new RowMapper<Object>() {
+                @Override
+                public Object mapRow(ResultSet rs, int i) throws SQLException {
+                    System.out.println(String.format("id:%s,first_name:%s,last_name:%s",
+                        rs.getString("id"),
+                        rs.getString("first_name"),
+                        rs.getString("last_name")));
+                    return null;
+                }
+            });
+    }
+}

spring-boot-h2/spring-boot-h2-database/src/main/java/com/baeldung/h2db/demo/server/SpringBootApp.java

@@ -1,4 +1,4 @@
-package com.baeldung.h2db.demo;
+package com.baeldung.h2db.demo.server;
 
 import java.sql.ResultSet;
 import java.sql.SQLException;
@@ -9,10 +9,12 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.core.RowMapper;
 
 @SpringBootApplication
+@ComponentScan("com.baeldung.h2db.demo.server")
 public class SpringBootApp {
 
     @Autowired
@@ -24,8 +26,7 @@ public class SpringBootApp {
 
     @PostConstruct
     private void initDb() {
-        System.out.println(String.format(
-            "****** Creating table: %s, and Inserting test data ******", "Employees"));
+        System.out.println(String.format("****** Creating table: %s, and Inserting test data ******", "Employees"));
 
         String sqlStatements[] = {
             "drop table employees if exists",
@@ -57,4 +58,4 @@ public class SpringBootApp {
     public Server inMemoryH2DatabaseServer() throws SQLException {
         return Server.createTcpServer("-tcp", "-tcpAllowOthers", "-tcpPort", "9091");
     }
-}
+}