1, 增加Maven依赖：
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
2, 增加Build的Maven插件
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
3，打开开发工具的 build Automatically
eclips：
general-workSpace-build-build Automatically
idea：
File-Settings-Compiler-Build Project automatically