SpringBoot private final注入Service报默认构造器未初始化错误

SpringBoot初学者开发缓存相关应用时，项目构建阶段持续抛出如下错误：

error: variable myApplicationService not initialized in the default constructor
对照参考教程无法理解对应字段的初始化逻辑，曾尝试添加@Autowired注解注入，但该方式已不被推荐，且添加后项目构建依然失败。

PersonController 代码 #

package com.springbootredis.controllers;

import com.springbootredis.service.MyApplicationService;
import lombok.AllArgsConstructor;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.UUID;

@RestController
@AllArgsConstructor
@RequestMapping(value = "/person", produces = { MediaType.APPLICATION_JSON_VALUE })
public class PersonController {

    private final MyApplicationService myApplicationService;// 报错位置

    @GetMapping("/uuid")
    public String generateRandomUUID() {
        return UUID.randomUUID().toString();
    }

    @GetMapping("/addperson/{name}")
    public String addPerson(@PathVariable String name) {
        String ret = myApplicationService.addNewPerson(name);
        return "Added person with name: " + name + " and id: " + ret;
    }


    @GetMapping("/deleteperson/{id}")
    public String deletePerson(@PathVariable String id) {
        String ret = myApplicationService.delete(id);
        return "Deleted person. ID:" + id + " Name: " + ret;
    }

    @GetMapping("/updateperson/{id}/{name}")
    public String updatePerson(@PathVariable String id, @PathVariable String name) {
        myApplicationService.updatePerson(id, name);
        return "Updated person. ID:" + id + " with Name: " + name;
    }

    @GetMapping("/getperson/{id}")
    public String getPerson(@PathVariable String id) {
        String ret = myApplicationService.findById(id);
        return "Got person. ID:" + id + " Name: " + ret;
    }
}

build.gradle 配置 #

plugins {
    id 'org.springframework.boot' version '2.7.1'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
    id 'war'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
    implementation("org.springframework.boot:spring-boot-starter-data-redis:2.7.0")
    implementation("org.springframework.boot:spring-boot-starter-cache:2.7.1")
    implementation("org.projectlombok:lombok:1.18.24")
    implementation("org.springframework.boot:spring-boot-dependencies:2.7.1")

    runtimeOnly("mysql:mysql-connector-java:8.0.29")

    providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

tasks.named('test') {
    useJUnitPlatform()
}

报错核心原因是Lombok的@AllArgsConstructor注解没有在编译期正常生成包含所有final字段的全参构造器，Spring无法通过构造器完成依赖注入，只能调用默认无参构造实例化对象，导致final字段未被初始化。按以下步骤逐一排查即可：

• 确认IDE的Lombok环境配置正常：安装对应IDE版本的Lombok插件，同时开启注解处理开关。以IDEA为例，路径为Settings > Build, Execution, Deployment > Compiler > Annotation Processors，勾选Enable annotation processing。
• 修正Lombok依赖配置：当前配置中Lombok仅声明为implementation作用域，Gradle编译阶段不会触发Lombok的注解处理逻辑。需要将原有Lombok依赖替换为如下配置，覆盖编译、测试全阶段的注解处理需求：

compileOnly "org.projectlombok:lombok:1.18.24"
annotationProcessor "org.projectlombok:lombok:1.18.24"
testCompileOnly "org.projectlombok:lombok:1.18.24"
testAnnotationProcessor "org.projectlombok:lombok:1.18.24"

• 移除多余依赖：删除dependencies中implementation("org.springframework.boot:spring-boot-dependencies:2.7.1")配置，该依赖集已经通过io.spring.dependency-management插件自动完成版本管理，手动引入容易引发依赖冲突，间接导致注解处理器运行异常。
• 确认待注入的Service被Spring容器管理：检查MyApplicationService的实现类上是否添加了@Service、@Component等构造型注解，且类所在包路径在SpringBoot启动类的组件扫描范围内，避免修复编译问题后出现Bean找不到的运行时错误。
• 清理构建缓存重新编译：在项目根目录执行./gradlew clean build命令，清除之前的错误编译产物后重新构建项目。

内容的提问来源于stack exchange，提问作者Ken