请教，对象没有使用 @Autowired 和 @Resource, 它是怎么注入的?

项目：el-admin

deptService 对象没有用过注解, 为什么还能调用 deptService.download ? 有没有大佬知道这个对象是怎么被实例化的?

代码如下：

/*
 *  Copyright 2019-2020 Zheng Jie
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package me.zhengjie.modules.system.rest;

import cn.hutool.core.collection.CollectionUtil;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.RequiredArgsConstructor;
import me.zhengjie.annotation.Log;
import me.zhengjie.exception.BadRequestException;
import me.zhengjie.modules.system.domain.Dept;
import me.zhengjie.modules.system.service.DeptService;
import me.zhengjie.modules.system.service.dto.DeptDto;
import me.zhengjie.modules.system.service.dto.DeptQueryCriteria;
import me.zhengjie.utils.PageResult;
import me.zhengjie.utils.PageUtil;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.security.access.prepost.PreAuthorize;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.*;
import javax.servlet.http.HttpServletResponse;
import java.util.*;
import java.util.stream.Collectors;

/**
* @author Zheng Jie
* @date 2019-03-25
*/
@RestController
@RequiredArgsConstructor
@Api(tags = "系统：部门管理")
@RequestMapping("/api/dept")
public class DeptController {

    private final DeptService deptService;
    private static final String ENTITY_NAME = "dept";

    @ApiOperation("导出部门数据")
    @GetMapping(value = "/download")
    @PreAuthorize("@el.check('dept:list')")
    public void exportDept(HttpServletResponse response, DeptQueryCriteria criteria) throws Exception {
        deptService.download(deptService.queryAll(criteria, false), response);
    }

    // ...
}

查看更多