Spring Framework

mvn archetype:generate \
    -DarchetypeArtifactId=maven-archetype-quickstart \
    -DinteractiveMode=false -DgroupId=io.github.jeanhwea -DartifactId=mapp

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>5.2.4.RELEASE</version>
</dependency>

mvn exec:java -Dexec.mainClass="io.github.jeanhwea.App" -Dexec.classpathScope=runtime

package com.xyz.someapp;

import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;

@Aspect
public class SystemArchitecture {

    /
     * A join point is in the web layer if the method is defined
     * in a type in the com.xyz.someapp.web package or any sub-package
     * under that.
     /
    @Pointcut("within(com.xyz.someapp.web..)")
    public void inWebLayer() {}

    /
     * A join point is in the service layer if the method is defined
     * in a type in the com.xyz.someapp.service package or any sub-package
     * under that.
     /
    @Pointcut("within(com.xyz.someapp.service..)")
    public void inServiceLayer() {}

    /
     * A join point is in the data access layer if the method is defined
     * in a type in the com.xyz.someapp.dao package or any sub-package
     * under that.
     /
    @Pointcut("within(com.xyz.someapp.dao..)")
    public void inDataAccessLayer() {}

    /
     * A business service is the execution of any method defined on a service
     * interface. This definition assumes that interfaces are placed in the
     * "service" package, and that implementation types are in sub-packages.
     *
     * If you group service interfaces by functional area (for example,
     * in packages com.xyz.someapp.abc.service and com.xyz.someapp.def.service) then
     * the pointcut expression "execution(* com.xyz.someapp..service..(..))"
     * could be used instead.
     *
     * Alternatively, you can write the expression using the 'bean'
     * PCD, like so "bean(Service)". (This assumes that you have
     * named your Spring service beans in a consistent fashion.)
     */
    @Pointcut("execution( com.xyz.someapp..service..(..))")
    public void businessService() {}

    /*
     * A data access operation is the execution of any method defined on a
     * dao interface. This definition assumes that interfaces are placed in the
     * "dao" package, and that implementation types are in sub-packages.
     */
    @Pointcut("execution( com.xyz.someapp.dao..(..))")
    public void dataAccessOperation() {}

}

@RestController
@RequestMapping("/persons")
class PersonController {

  @GetMapping("/{id}")
  public Person getPerson(@PathVariable Long id) { /* ... */ }

  @PostMapping
  @ResponseStatus(HttpStatus.CREATED)
  public void add(@RequestBody Person person) { /* ... */ }

}

@GetMapping("/owners/{ownerId}/pets/{petId}")
public Pet findPet(@PathVariable Long ownerId, @PathVariable Long petId) { /* ... */ }

@GetMapping("/pets/{petId}")
public Pet findPet(@PathVariable("petId") id) { /* ... */ }

@GetMapping("/{name:[a-z-]+}-{version:\\d\\.\\d\\.\\d}{ext:\\.[a-z]+}")
public void handle(@PathVariable String version, @PathVariable String ext) { /* ... */ }

@GetMapping("/pets/{petId}")
// same as
@RequestMapping("/pets/{petId}", method=HttpMethod.GET)

@PostMapping(path = "/pets", consumes = "application/json")
public void addPet(@RequestBody Pet pet) { /* ... */ }

@PostMapping(path = "/pets", consumes = "!text/plain")
public void addPet(@RequestBody Pet pet) { /* ... */ }

@GetMapping(path = "/pets/{petId}", produces = "application/json")
@ResponseBody
public Pet getPet(@PathVariable String petId) { /* ... */ }

@GetMapping(path = "/pets/{petId}", params = "myParam=myValue")
public void findPet(@PathVariable String petId) { /* ... */ }

@GetMapping(path = "/pets", headers = "myHeader=myValue")
public void findPet(@PathVariable String petId) { /* ... */}

@Configuration
public class MyConfig {

  @Autowired
  public void setHandlerMapping(RequestMappingHandlerMapping mapping, UserHandler handler)
    throws NoSuchMethodException {

    RequestMappingInfo info = RequestMappingInfo
      .paths("/user/{id}").methods(RequestMethod.GET).build();

    Method method = UserHandler.class.getMethod("getUser", Long.class);

    mapping.registerMapping(info, handler, method);
  }
}

// GET /pets/42;q=11;r=22
@GetMapping("/pets/{petId}")
public void findPet(@PathVariable String petId, @MatrixVariable int q) {
  // petId == 42
  // q == 11
}

// GET /owners/42;q=11/pets/21;q=22
@GetMapping("/owners/{ownerId}/pets/{petId}")
public void findPet(@MatrixVariable(name="q", pathVar="ownerId") int q1,
               @MatrixVariable(name="q", pathVar="petId") int q2) {
  // q1 == 11
  // q2 == 22
}

// GET /pets/42
@GetMapping("/pets/{petId}")
public void findPet(@MatrixVariable(required=false, defaultValue="1") int q) {
  // q == 1
}

// GET /owners/42;q=11;r=12/pets/21;q=22;s=23
@GetMapping("/owners/{ownerId}/pets/{petId}")
public void findPet(@MatrixVariable MultiValueMap<String, String> matrixVars,
               @MatrixVariable(pathVar="petId") MultiValueMap<String, String> petMatrixVars) {
  // matrixVars: ["q" : [11,22], "r" : 12, "s" : 23]
  // petMatrixVars: ["q" : 22, "s" : 23]
}

@Controller
@RequestMapping("/pets")
public class EditPetForm {
  @GetMapping
  public String setupForm(@RequestParam("petId") int petId, Model model) {
    Pet pet = this.clinic.loadPet(petId);
    model.addAttribute("pet", pet);
    return "petForm";
  }
}

@GetMapping("/demo")
public void handle(@RequestHeader("Accept-Encoding") String encoding,
              @RequestHeader("Keep-Alive") long keepAlive) {
}

@GetMapping("/demo")
public void handle(@CookieValue("JSESSIONID") String cookie) {
}

@Controller
public class FileUploadController {

  @PostMapping("/form")
  public String handleFormUpload(@RequestParam("name") String name,
                            @RequestParam("file") MultipartFile file) {
    if (!file.isEmpty()) {
      byte[] bytes = file.getBytes();
      // store the bytes somewhere
      return "redirect:uploadSuccess";
    }
    return "redirect:uploadFailure";
  }
}

@Controller
public class SimpleController {
  @ExceptionHandler
  public ResponseEntity<String> handle01(IOException ex) { /* ... */ }

  @ExceptionHandler({FileSystemException.class, RemoteException.class})
  public ResponseEntity<String> handle02(IOException ex) { /* ... */ }

  @ExceptionHandler({FileSystemException.class, RemoteException.class})
  public ResponseEntity<String> handle(Exception ex) { /* ... */ }
}

// Target all Controllers annotated with @RestController
@ControllerAdvice(annotations = RestController.class)
public class ExampleAdvice1 {}

// Target all Controllers within specific packages
@ControllerAdvice("org.example.controllers")
public class ExampleAdvice2 {}

// Target all Controllers assignable to specific classes
@ControllerAdvice(assignableTypes = {ControllerInterface.class, AbstractController.class})
public class ExampleAdvice3 {}

@RestController
@RequestMapping("/account")
public class AccountController {

  @CrossOrigin
  @GetMapping("/{id}")
  public Account retrieve(@PathVariable Long id) { /* ... */ }

  @DeleteMapping("/{id}")
  public void remove(@PathVariable Long id) { /* ... */ }
}

@CrossOrigin(origins = "https://domain2.com", maxAge = 3600)
@RestController
@RequestMapping("/account")
public class AccountController {

  @GetMapping("/{id}")
  public Account retrieve(@PathVariable Long id) { /* ... */ }

  @DeleteMapping("/{id}")
  public void remove(@PathVariable Long id) { /* ... */ }
}

@CrossOrigin(maxAge = 3600)
@RestController
@RequestMapping("/account")
public class AccountController {

  @CrossOrigin("https://domain2.com")
  @GetMapping("/{id}")
  public Account retrieve(@PathVariable Long id) { /* ... */ }

  @DeleteMapping("/{id}")
  public void remove(@PathVariable Long id) { /* ... */ }
}

@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {

  @Override
  public void addCorsMappings(CorsRegistry registry) {

    registry.addMapping("/api/**")
      .allowedOrigins("https://domain2.com")
      .allowedMethods("PUT", "DELETE")
      .allowedHeaders("header1", "header2", "header3")
      .exposedHeaders("header1", "header2")
      .allowCredentials(true).maxAge(3600);

    // Add more mappings...
  }
}

public interface OrderManager {
  void placeOrder(Order order);
}

import org.springframework.mail.MailException;
import org.springframework.mail.MailSender;
import org.springframework.mail.SimpleMailMessage;

public class SimpleOrderManager implements OrderManager {

  private MailSender mailSender;
  private SimpleMailMessage templateMessage;

  public void setMailSender(MailSender mailSender) {
    this.mailSender = mailSender;
  }

  public void setTemplateMessage(SimpleMailMessage templateMessage) {
    this.templateMessage = templateMessage;
  }

  public void placeOrder(Order order) {
    // 1. 处理业务逻辑 ...
    // 2. 调用协调模块，处理发送的顺序 ...
    // 3. 复制模板，使用线程安全的模板进入发送队列
    SimpleMailMessage msg = new SimpleMailMessage(this.templateMessage);
    msg.setTo(order.getCustomer().getEmailAddress());
    msg.setText("Dear " + order.getCustomer().getFirstName()
                + order.getCustomer().getLastName()
                + ", thank you for placing order. Your order number is "
                + order.getOrderNumber());
    try{
      this.mailSender.send(msg);
    } catch (MailException ex) {
      // simply log it and go on...
      System.err.println(ex.getMessage());
    }
  }

}

@Configuration
@EnableAsync
@EnableScheduling
public class AppConfig {
}

@Scheduled(fixedDelay=5000)
public void doSomething() {
  // something that should execute periodically
}

@Scheduled(initialDelay=1000, fixedRate=5000)
public void doSomething() {
  // something that should execute periodically
}

@Scheduled(cron="*/5 * * * * MON-FRI")
public void doSomething() {
  // something that should execute on weekdays only
}

@Async
void doSomething() {
  // this will be executed asynchronously
}

@Async
void doSomething(String s) {
  // this will be executed asynchronously
}

@Async
Future<String> returnSomething(int i) {
  // this will be executed asynchronously
}

public class MyAsyncUncaughtExceptionHandler implements AsyncUncaughtExceptionHandler {
  @Override
  public void handleUncaughtException(Throwable ex, Method method, Object... params) {
    // 处理异常逻辑
  }
}