Thursday, December 26, 2019

Spring Cloud 微服務入門 (四) Eureka + Consumer (Feign) Rest 傳遞參數

feign 如何調用 service 且傳入參數

比較常見就是這兩種
@GetMapping
@PostMapping
這兩種又有
@RequestMappin
此文章沒討論用這個@RequestMapping 這算是比較舊的寫法，或許後續有空會補上
通常我們呼叫 restAPi可以用
@GetMapping
@PostMapping
那麼又有分
  • 無參數
  • 單參數
  • 多個參數
  • 複雜對象

單參數

無參數就不多加實作了主要針對有參數的

Provider Controller

@SpringBootApplication
@EnableEurekaClient
@RestController
public class EurekaServiceProviderApplication {
 
 @Value("${server.port}")
     String port;
  @GetMapping("/")
 public String home(@RequestParam (value="id", required = false) Integer employeeId) {
       return "Hello world" + port+ employeeId;
 }
 public static void main(String[] args) {
  SpringApplication.run(EurekaServiceProviderApplication.class, args);
 }

}

Consumer 接口

@FeignClient("eureka-provider")
public interface HomeClient {
  @GetMapping("/")
  public String home(@RequestParam (value="id", required = false) Integer employeeId) ;
}

Consumer Controller

@RestController
public class ConsumerController {
  @Autowired
     private HomeClient homeClient;

 
   @GetMapping("/hello/{id}")
     public String hello(@PathVariable(name="id") Integer employeeId) {
      System.out.print(employeeId);
         return homeClient.home(employeeId);
     }
}

多參數

Provider Controller

@SpringBootApplication
@EnableEurekaClient
@RestController
public class EurekaServiceProviderApplication {
 
 @Value("${server.port}")
     String port;
  @GetMapping("/")
  public String home(@RequestParam (value="id", required = false) Integer employeeId,@RequestParam (value="id2", required = false) Integer employeeId2)  {
       return "Hello world" + port+ employeeId+employeeId2;
 }
 public static void main(String[] args) {
  SpringApplication.run(EurekaServiceProviderApplication.class, args);
 }

}

Consumer 接口

@FeignClient("eureka-provider")
public interface HomeClient {
  @GetMapping("/")
  public String home(@RequestParam (value="id", required = false) Integer employeeId,@RequestParam (value="id2", required = false) Integer employeeId2) ;
}

Consumer Controller

@RestController
public class ConsumerController {
  @Autowired
     private HomeClient homeClient;

 
   @GetMapping("/hello/{id}/{id2}")
     public String hello(@PathVariable(name="id") Integer employeeId,@PathVariable(name="id2") Integer employeeId2) {
      System.out.print(employeeId2);
         return homeClient.home(employeeId,employeeId2);
     }
}
詳細可以參考
SpringBoot 中常用注解@PathVaribale/@RequestParam/@GetMapping介绍
http://www.itmuch.com/spring-cloud-sum/feign-multiple-params/

複雜對象

構建一個 entity
UserEntity.class
這邊好像在一個網站有看過這邊大小寫 windows 沒有限制，在linux 就嚴格 限制 大小寫，後面會來好好講解，
然後這個 Entity 同時在 Provider 和 Consumer 裡。
public class UserEntity {
 
 private Integer id;

 private String Name ;

 private Integer age;
 
 public Integer getId() {
  return id;
 }
 public void setId(Integer id) {
  this.id = id;
 }
 public String getName() {
  return Name;
 }
 public void setName(String name) {
  Name = name;
 }
 public Integer getAge() {
  return age;
 }
 public void setAge(Integer age) {
  this.age = age;
 }
}

Provider


public class UserEntity {
 
 private Integer id;

 private String Name ;

 private Integer age;
 
 public Integer getId() {
  return id;
 }
 public void setId(Integer id) {
  this.id = id;
 }
 public String getName() {
  return Name;
 }
 public void setName(String name) {
  Name = name;
 }
 public Integer getAge() {
  return age;
 }
 public void setAge(Integer age) {
  this.age = age;
 }
}

Consumer 接口

@FeignClient("eureka-provider")
public interface HomeClient {
  @GetMapping("/")
  public String home(@RequestParam (value="id", required = false) Integer employeeId,@RequestParam (value="id2", required = false) Integer employeeId2) ;
  @PostMapping("/user")
  public String aveUser(@RequestBody UserEntity user);
}

Consumer Controller

@RestController
public class ConsumerController {
  @Autowired
     private HomeClient homeClient;

 
   @GetMapping("/hello/{id}/{id2}")
     public String hello(@PathVariable(name="id") Integer employeeId,@PathVariable(name="id2") Integer employeeId2) {
      System.out.print(employeeId2);
         return homeClient.home(employeeId,employeeId2);
     }
   
  @PostMapping("/user")
   public String aveUser(@RequestBody UserEntity user) {
    return homeClient.aveUser(user);
  }

}

運行並測試

注意大小寫


大概變化就這幾種
接下來就輪到介紹我們的 Hystrix 斷路器。
於
標籤： , ,