在Spring1.x时代，还没出现注解，需要大量xml配置文件并在内部编写大量bean标签。Java5推出新特性annotation，为spring的更新奠定了基础。从Spring 2.X开始spring将xml配置中的对象ioc过程转化成了注解。Spring Boot之所以能够轻松地实现应用的创建及与其他框架快速集成，最核心的原因就在于它极大地简化了项目的配置，最大化地实现了“约定大于配置”的原则。但是注解种类之繁多，还能容易引起混淆，这才有了本文《SpringBoot进阶教程(六十四)注解大全》。

要想对SpringBoot注解有个更全面更清晰的认识，就需要分个类，分别是Spring注解、Spring Web注解、Spring Boot注解、Spring Scheduling注解和注解集合。大致可以将注解分为5大类，其中前4类是为了便于理解，分别从4个类别中抽取了一些单独介绍。而最后一个为注解集合，即可能会包含前面4种注解。

@RestController

public class UserController {

    private UserService userService;

    @Autowired

    public UserController(UserService userService) {

        this.userService = userService;

    }

}

@RestController

public class UserController {

    private UserService userService;

    @Autowired

    public void setUserService(UserService userService) {

        this.userService = userService;

    }

}

@RestController

public class UserController {

    @Autowired

    private UserService userService;

}

@Component("studentInfo")

public class StudentInfo implements UserInfo {

    public String userName() {

        return "student";

    }

}

@Component("teacherInfo")

public class TeacherInfo implements UserInfo {

    public String userName {

        return "teacher";

    }

}

@Component

public class UserService {

    @Autowired

    @Qualifier("studentInfo")

    private UserInfo userInfo;

    //todo

}

@Configuration

public class BeanConfig {

    @Bean

    public Person userInfo() {

        return new UserInfo("toutou", 18);

    }

}

<bean id="userInfo" class="com.test.UserInfo">

    <property name="age" value="18"/>

    <property name="name" value="请叫我头头哥 http://toutou.cnblogs.com"/>

</bean>

@Required

void setUserName(String name) {

    this.name = name;

}

<bean class="com.test.UserInfo">

    <property name="name" value="请叫我头头哥 https://www.cnblogs.com/toutou/" />

</bean>

public class FirstBean {

    @Autowired

    private SecondBean secondBean;

}

public class SecondBean {

    public SecondBean() {

        System.out.println("SecondBean init");

    }

}

@Configuration

public class BeanConfig {

    @Bean("firstBean")

    @DependsOn(value = {

        "secondBean"

    })

    public FirstBean firstBean() {

        return new FirstBean();

    }

    @Bean("secondBean")

    public SecondBean secondBean() {

        return new SecondBean();

    }

}

public class FirstBean {

    public void test() {

        System.out.println("FirstBean Class");

    }

}

public class SecondBean {

    public void test() {

        System.out.println("SecondBean Class");

    }

}

@Configuration

public class AppConfig {

    @Lazy(value = true)

    @Bean

    public FirstBean firstBean() {

        return new FirstBean();

    }

    @Bean

    public SecondBean secondBean() {

        return new SecondBean();

    }

}

@Component("studentInfo")

public class StudentInfo implements UserInfo {

    public String userName() {

        return "student";

    }

}

@Component("teacherInfo")

@Primary

public class TeacherInfo implements UserInfo {

    public String userName {

        return "teacher";

    }

}

@Component

public class UserService {

    @Autowired

    @Qualifier("studentInfo")

    private UserInfo userInfo;

    //todo

}

@Configuration

public class ConfigA {

    @Bean

    public A a() {

        return new A();

    }

}

@Configuration

@Import(ConfigA.class)

public class ConfigB {

    @Bean

    public B b() {

        return new B();

    }

}

@Configuration

@ImportResource({"classpath*:applicationContext.xml"})

public class XmlConfiguration {

}

@Configuration

@PropertySource("classpath:config.properties")

public class ProperySourceDemo implements InitializingBean {

    @Autowired

    Environment env;

    @Override

    public void afterPropertiesSet() throws Exception {

        setDatabaseConfig();

    }

    private void setDatabaseConfig() {

        DataSourceConfig config = new DataSourceConfig();

        config.setDriver(env.getProperty("jdbc.driver"));

        config.setUrl(env.getProperty("jdbc.url"));

        config.setUsername(env.getProperty("jdbc.username"));

        config.setPassword(env.getProperty("jdbc.password"));

        System.out.println(config.toString());

    }

}

@PropertySources({

  @PropertySource("classpath:config.properties"),

  @PropertySource("classpath:db.properties")

 })

 public class AppConfig {

  //todo...

 }

@RestController

@RequestMapping("/api/v1")

public class UserController {

    @Autowired

    private UserService userService;

    @PostMapping("/user")

    public UserInfo createUser(@Valid @RequestBody UserInfo user) {

        return userService.save(user);

    }

}

@Controller

class UserController {

    @RequestMapping(value = "/user/index", method = RequestMethod.GET)

    String index() {

        return "index";

    }

}

    @GetMapping("/users")

    public List<user> getAllUser() {

        //...

    }

    @GetMapping("/users/{id}")

    public ResponseEntity<User> getUserById(@PathVariable(value = "id") Long userId)

            throws ResourceNotFoundException {

        user user = userRepository.findById(userId)

                .orElseThrow(() -> new ResourceNotFoundException("user not found for this id :: " + userId));

        return ResponseEntity.ok().body(user);

    }

@PostMapping("/user/add")

public User addUser(@Valid @RequestBody User user) {

 return userRepository.save(user);

}

@ControllerAdvice(basePackages = {"com.toutou.controller"} )

public class GlobalControllerAdvice {

    @InitBinder

    public void dataBinding(WebDataBinder binder) {

        SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy");

        dateFormat.setLenient(false);

        binder.registerCustomEditor(Date.class, "dob", new CustomDateEditor(dateFormat, true));

    }

    @ModelAttribute

    public void globalAttributes(Model model) {

        model.addAttribute("msg", "Hello World!");

    }

    @ExceptionHandler(FileNotFoundException.class)

    public ModelAndView myError(Exception exception) {

        ModelAndView mav = new ModelAndView();

        mav.addObject("exception", exception);

        mav.setViewName("error");

        return mav;

    }

}

@CrossOrigin(origins = "http://toutou.com", maxAge = 3600)

@RequestMapping("/index")

String index() {

    return "Hello World!";

}

@SpringBootApplication // 等于：@Configuration @EnableAutoConfiguration @ComponentScan

public class Application {

    public static void main(String[] args) {

        SpringApplication.run(Application.class, args);

    }

}

@EnableAutoConfiguration

public class Application {

    public static void main(String[] args) {

        SpringApplication.run(Application.class, args);

    }

}

@ConditionalOnBean         //    当给定的在bean存在时,则实例化当前Bean

@ConditionalOnMissingBean  //    当给定的在bean不存在时,则实例化当前Bean

@ConditionalOnClass        //    当给定的类名在类路径上存在，则实例化当前Bean

@ConditionalOnMissingClass //    当给定的类名在类路径上不存在，则实例化当前Bean

@Scheduled(fixedDelay=1000)

public void doSomething() {

    //...

}

@Configuration

@EnableScheduling //通过@EnableScheduling注解开启对计划任务的支持

public class TaskScheduleConfig {

    //...

}

作　　者：请叫我头头哥


出　　处：http://www.cnblogs.com/toutou/


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