Spring Boot项目Jar转War部署Tomcat8.5.9出现404错误求助

问题描述 #

将Spring Boot应用从Jar包转换为War包后，部署到Tomcat 8.5.9服务器时出现404错误。

相关代码配置 #

启动类代码 #

@SpringBootApplication
public class SpringApiApplication extends SpringBootServletInitializer implements WebApplicationInitializer {
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(SpringApiApplication.class);
    }

    public static void main(String[] args) throws Exception {
        SpringApplication.run(SpringApiApplication.class, args);
    }
}

控制器代码 #

// 控制器代码
package com.javaproject.springapi.controller;

import java.util.List;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.javaproject.springapi.model.Student;
import com.javaproject.springapi.service.StudentService;

@RestController
@RequestMapping("/api")
public class StudentController {
   
    private StudentService studentService;

    public StudentController(StudentService studentService) {
        super();
        this.studentService = studentService;
    }
    
    @PostMapping()
    public ResponseEntity<Student> addStudent(@RequestBody Student student){
        return new ResponseEntity<>(studentService.addStudent(student), HttpStatus.CREATED);
    }
    
    @GetMapping
    public List<Student> getStudents(){
        return studentService.getStudents();
    }
    
    // 根据ID查询学生
    @GetMapping("{id}")
    public ResponseEntity<Student> getStudentById(@PathVariable("id") long stuId){
        return new ResponseEntity<>(studentService.getStudentById(stuId), HttpStatus.OK);
    }
    
    // 更新学生信息
    @PutMapping("{id}")
    public ResponseEntity<Student> updateStudent(@PathVariable("id") long id, @RequestBody Student student){
        return new ResponseEntity<>(studentService.updateStudent(student, id), HttpStatus.OK);
    }
    
    // 删除学生
    @DeleteMapping("{id}")
    public ResponseEntity<String> deleteStudent(@PathVariable("id") long id){
        studentService.deleteStudent(id); 
        return new ResponseEntity<>("学生删除成功！", HttpStatus.OK);
    }
}

pom.xml配置 #

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.3</version>
        <relativePath/>
    </parent>
    <groupId>com.springboot.app</groupId>
    <artifactId>springboot-war-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>springboot-war-demo</name>
    <description>Spring Boot WAR Demo</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

问题排查与解决 #

1. 版本兼容性问题（核心原因） #

• Spring Boot 2.7.3依赖Servlet API 4.0，而Tomcat 8.5.9仅支持Servlet API 3.1，版本不匹配导致应用无法正常初始化。
• Java 17与Tomcat 8.5.9不兼容，Tomcat 8.5最高仅支持Java 11。

解决方法二选一：

• 升级Tomcat到9.0.x版本（推荐9.0.60+，支持Java 8-17，与Spring Boot 2.7.3兼容）。
• 降级Spring Boot到2.3.x及以下版本（支持Tomcat 8.5），同时将Java版本降至11或更低。

2. 访问路径错误 #

War包部署到Tomcat后，访问路径需包含War包名称，例如：

• 若War包名为springboot-war-demo.war，正确访问地址应为 http://localhost:8080/springboot-war-demo/api，而非直接访问http://localhost:8080/api。

3. 启动类优化 #

启动类无需额外实现WebApplicationInitializer，因为SpringBootServletInitializer已实现该接口，修改后代码如下：

@SpringBootApplication
public class SpringApiApplication extends SpringBootServletInitializer {
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(SpringApiApplication.class);
    }

    public static void main(String[] args) throws Exception {
        SpringApplication.run(SpringApiApplication.class, args);
    }
}

4. 验证应用启动状态 #

查看Tomcat的logs/catalina.out日志，确认应用是否成功启动，若存在类加载异常、依赖缺失等错误，需针对性修复。

内容的提问来源于stack exchange，提问作者Shalini