Bean注入的多种方式

曾经终败给现在 2024-03-22 14:40 14阅读 0赞

### 1.@AutoWired ###

@RestController
    public class DemoTest {
        
        @Autowired
        private UserService userService;
    
        @GetMapping("/test")
        public ResultVo test(){
        
            List<User> userList = userService.findAll();
            return ResultVo.ok().data("list",userList);
        }
    }

### 2.@Resource ###

@RestController
    public class DemoTest {
        
        @Resource
        private UserService userService;
    
        @GetMapping("/test")
        public ResultVo test(){
        
            List<User> userList = userService.findAll();
            return ResultVo.ok().data("list",userList);
        }
    }

### 3.set注入 ###

@RestController
    public class DemoTest {
        
        UserService userService;
    
        //基于set注入 ，添加 @Autowired 注解
        @Autowired
        public void setUserService(UserService userService){
        
            this.userService=userService;
        }
    
        @GetMapping("/test")
        public ResultVo test(){
        
            List<User> userList = userService.findAll();
            return ResultVo.ok().data("list",userList);
        }
    }

### 4.构造器注入 ###

@RestController
    public class DemoTest {
        
        UserService userService;
    
        //基于构造方法注入
        public DemoTest(UserService userService) {
        
            this.userService = userService;
        }
    
        @GetMapping("/test")
        public ResultVo test(){
        
            List<User> userList = userService.findAll();
            return ResultVo.ok().data("list",userList);
        }
    }

### 5.@RequiredArgsConstructor ###

@RestController
    @RequiredArgsConstructor # 添加 @RequiredArgsConstructor 注解
    public class DemoTest {
        
        
        //# 必须添加final关键字
        private final UserService userService;
    
        @GetMapping("/test")
        public ResultVo test(){
        
            List<User> userList = userService.findAll();
            return ResultVo.ok().data("list",userList);
        }
    }