在pom.xml中加入下面的依賴就可以用了 

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-devtools</artifactId>
</dependency>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
                <fork>true</fork>
            </configuration>
        </plugin>
    </plugins>
</build>