关于springboot:Springboot项目打war包流程及过程中出现的问题

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1. 将 Application 启动类所在的 module 中的 pom 文件，把 <packaging> 标签批改成

<packaging>war</packaging>

2. 移除自带内置 tomcat

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </exclusion>
    </exclusions>
</dependency>

3. 增加 servlet 依赖

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <scope>provided</scope>
</dependency>

4. 减少 war 的启动类

class WarStarterApplication extends SpringBootServletInitializer {

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
        //  指向 Application 这个 springboot 启动类
        return builder.sources(Application.class);
    }
}

实现以上步骤后，应用 maven 的 package 性能打包即能放到 tomcat 中运行。

此时，如果想在我的项目中持续应用启动类运行我的项目，会呈现“Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean.”报错，但在 tomcat 中是能失常运行的。

2021-08-30 11:00:05 ERROR SpringApplication:858 - Application run failed
org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.context.ApplicationContextException: Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean.
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:157)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543)
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:316)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248)
    at com.jimmy.Application.main(Application.java:25)
Caused by: org.springframework.context.ApplicationContextException: Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean.
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.getWebServerFactory(ServletWebServerApplicationContext.java:206)
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:180)
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:154)
    ... 8 more

呈现该谬误的起因是上述步骤 2，移除了内置的 tomcat，而放在 tomcat 中的 war 包能失常运行，是因为 tomcat 中已自带了这个相干的包。

如果想持续在 IDE 中应用启动类启动我的项目，只须要将步骤 2 移除内置 tomcat 的步骤正文即可。

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