Ribben以及Feign实现负载均衡

SpringCloud
Ribbon是基于Netflix Ribben实现的一套 客户端负载均衡的工具 通过微服务名字访问

@RestController
public class DeptConsumerController {
    //消费者不应该有service层
    //支持restful风格请求
    //RestTemplate 模板 可以直接调用（首先注册到Spring中）
    //    url地址  参数（map封装，实体，url传递）   class返回值
    //参数(String url, Class<T> responseType, Object... uriVariables)
    @Autowired
    private RestTemplate restTemplate;//提供多种便捷访问远程http的方法 简单的restful风格服务模板
    //通过Ribbon去请求服务器时 REST_URL_PREFIX应该是个变量，通过服务名来访问 http://localhost:8001
    private static final String REST_URL_PREFIX="http://SPRING-CLOUD-PROVIDER-DEPT";
    //url:http://localhost:8001/dept/getAll
    @RequestMapping("/consumer/dept/get1/{id}")
    public Dept get(@PathVariable("id") Long deptno){
        return restTemplate.getForObject (REST_URL_PREFIX+"/dept/get/"+deptno,Dept.class);
    }
    @RequestMapping("/consumer/dept/add")
    public boolean add(Dept dept)
    {
        return restTemplate.postForObject (REST_URL_PREFIX+"/dept/add/",dept,Boolean.class);
    }
    @RequestMapping("/consumer/dept/list")
    public List<Dept> getAll(){
        return restTemplate.getForObject (REST_URL_PREFIX+"/dept/getAll/",List.class);
    }
}

@RestController
public class DeptController {
    @Autowired
    private DeptService deptService;
    @Autowired   //获取具体信息，得到具体的服务
    private org.springframework.cloud.client.discovery.DiscoveryClient discoveryClient;
    @RequestMapping("/dept")
    @ResponseBody
    public String addDept11(){
        return "deptService.addDept (dept)";
    }
    @PostMapping("/dept/add")
    public boolean addDept(Dept dept){
        return deptService.addDept (dept);
    }
    @GetMapping("/dept/get/{deptno}")
    public Dept getDept(@PathVariable("deptno") Long deptno){
        System.out.println (deptno);
        return deptService.DeptById (deptno);
    }
    @GetMapping("/dept/getAll")
    public List<Dept> getAllDept(){
        System.out.println (deptService.queryAll ());
        return deptService.queryAll ();
    }
}

因为已经显示配置路径所以不需要消费者请求url名称与服务提供者请求url相同

Feign是基于webService客户端（增加一层Service，性能可能会变低），通过接口和注解访问（Feign本质还是Ribbon）

@Service
@FeignClient(value = "SPRING-CLOUD-PROVIDER-DEPT")
public interface DeptClientService {

    @GetMapping("/dept/get/{id}")   //需要与服务提供者端请求路径相同
    public Dept queryById(@PathVariable("id")Long deptno);
    @GetMapping("/dept/getAll")
    public List<Dept> queryAll();
    @PostMapping("/dept/add")
    public boolean addDept(Dept dept);

}


@RestController
public class DeptConsumerController {


    @Autowired
    DeptClientService deptClientService=null;

    @RequestMapping("/consumer/dept/get/{id}")
    public Dept get(@PathVariable("id") Long deptno){
        return this.deptClientService.queryById (deptno);
    }
    @RequestMapping("/consumer/dept/add")
    public boolean add(Dept dept)
    {
        return this.deptClientService.addDept (dept);
    }
    @RequestMapping("/consumer/dept/list")
    public List<Dept> getAll(){
        System.out.println (this.deptClientService.queryAll ());
        return this.deptClientService.queryAll ();
    }
}


@RestController
public class DeptController {
    @Autowired
    private DeptService deptService;
    @Autowired   //获取具体信息，得到具体的服务
    private org.springframework.cloud.client.discovery.DiscoveryClient discoveryClient;
    @RequestMapping("/dept")
    @ResponseBody
    public String addDept11(){
        return "deptService.addDept (dept)";
    }
    @PostMapping("/dept/add")
    public boolean addDept(Dept dept){
        return deptService.addDept (dept);
    }
    @GetMapping("/dept/get/{deptno}")
    public Dept getDept(@PathVariable("deptno") Long deptno){
        System.out.println (deptno);
        return deptService.DeptById (deptno);
    }
    @GetMapping("/dept/getAll")
    public List<Dept> getAllDept(){
        System.out.println (deptService.queryAll ());
        return deptService.queryAll ();
    }
}

没有显示配置路径，如果必须使Api Service层接口中路径与服务提供者相同，否则找不到页面