idea创建Springboot项目，最低版本只能选择java8，但是生产环境的jdk是1.7。
按java8创建好之后,先把jdk改了：
按对应关系修改pom中的Springboot版本：
org.springframework.boot spring-boot-starter-parent1.5.17.RELEASE
| Sping Boot | Spring Framework | Java | Maven | Gradle |
| Spring Boot 2.1.x | ||||
| 2.1.0.RELEASE | Spring Framework 5.1.2.RELEASE | Java 8 or 9 | 3.3+ | 4.4+ |
| Spring Boot 2.0.x | ||||
| 2.0.6.RELEASE | Spring Framework 5.0.10.RELEASE | Java 8 or 9 | 3.2+ | 4.x |
| 2.0.5.RELEASE | Spring Framework 5.0.9.RELEASE | 4.x | ||
| 2.0.4.RELEASE | Spring Framework 5.0.8.RELEASE | 4 | ||
| 2.0.3.RELEASE | Spring Framework 5.0.7.RELEASE | 4 | ||
| 2.0.2.RELEASE | Spring Framework 5.0.6.RELEASE | 4 | ||
| 2.0.1.RELEASE | Spring Framework 5.0.5.RELEASE | 4 | ||
| 2.0.0.RELEASE | Spring Framework 5.0.4.RELEASE | 4 | ||
| Spring Boot 1.5.x | ||||
| 1.5.17.RELEASE | Spring Framework 4.3.20.RELEASE | Java 7 | 3.2+ | [2.9, 3.x] |
| 1.5.16.RELEASE | Spring Framework 4.3.19.RELEASE | |||
| 1.5.15.RELEASE | Spring Framework 4.3.18.RELEASE | |||
| 1.5.14.RELEASE | Spring Framework 4.3.18.RELEASE | |||
| 1.5.13.RELEASE | Spring Framework 4.3.17.RELEASE | |||
| 1.5.12.RELEASE | Spring Framework 4.3.16.RELEASE | |||
| 1.5.11.RELEASE | Spring Framework 4.3.15.RELEASE | |||
| 1.5.10.RELEASE | Spring Framework 4.3.14.RELEASE | |||
| 1.5.9.RELEASE | Spring Framework 4.3.13.RELEASE | |||
| 1.5.8.RELEASE | Spring Framework 4.3.12.RELEASE | |||
| 1.5.7.RELEASE | Spring Framework 4.3.11.RELEASE | |||
| 1.5.6.RELEASE | Spring Framework 4.3.10.RELEASE | |||
| 1.5.5.RELEASE | Spring Framework 4.3.10.RELEASE | |||
| 1.5.4.RELEASE | Spring Framework 4.3.9.RELEASE | |||
| 1.5.3.RELEASE | Spring Framework 4.3.8.RELEASE | |||
| 1.5.2.RELEASE | Spring Framework 4.3.7.RELEASE | |||
| 1.5.1.RELEASE | Spring Framework 4.3.6.RELEASE | |||
| 1.5.0.RELEASE | Spring Framework 4.3.6.RELEASE | |||
| Spring Boot 1.4.x | ||||
| 1.4.7.RELEASE | Spring Framework 4.3.9.RELEASE | Java 7 | 3.2+ | [1.12, 2.x] |
| 1.4.6.RELEASE | Spring Framework 4.3.8.RELEASE | |||
| 1.4.5.RELEASE | Spring Framework 4.3.7.RELEASE | |||
| 1.4.4.RELEASE | Spring Framework 4.3.6.RELEASE | |||
| 1.4.3.RELEASE | Spring Framework 4.3.5.RELEASE | |||
| 1.4.2.RELEASE | Spring Framework 4.3.4.RELEASE | |||
| 1.4.1.RELEASE | Spring Framework 4.3.3.RELEASE | |||
| 1.4.0.RELEASE | Spring Framework 4.3.2.RELEASE | |||
| Spring Boot 1.3.x | ||||
| 1.3.8.RELEASE | Spring Framework 4.2.8.RELEASE | Java 7 | 3.2+ | [1.12, 2.x] |
| 1.3.7.RELEASE | Spring Framework 4.2.7.RELEASE | 1.12+ | ||
| 1.3.6.RELEASE | Spring Framework 4.2.7.RELEASE | |||
| 1.3.5.RELEASE | Spring Framework 4.2.6.RELEASE | |||
| 1.3.4.RELEASE | Spring Framework 4.2.6.RELEASE | |||
| 1.3.3.RELEASE | Spring Framework 4.1.5 or above | |||
| 1.3.2.RELEASE | ||||
| 1.3.1.RELEASE | ||||
| 1.3.0.RELEASE | ||||
| Spring Boot 1.2.x | ||||
| 1.2.8.RELEASE | Spring Framework 4.1.5 or above | Java 7 | 3.2+ | 1.12+ |
| 1.2.7.RELEASE | ||||
| 1.2.6.RELEASE | ||||
| 1.2.5.RELEASE | ||||
| 1.2.4.RELEASE | ||||
| 1.2.3.RELEASE | ||||
| 1.2.2.RELEASE | ||||
| 1.2.1.RELEASE | Spring Framework 4.1.3 or above | Java 6 | ||
| 1.2.0.RELEASE | ||||
直接修改
如果是打成war包，SpringBootServletInitializer需要修改，将引用里的servlet去掉即可：
jar包降级：
application配置文件修改：
server.servlet.context-path改为server.context-path
server: port: 8888 context-path: /app
配置修改结束，运行成功！
