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Ribbon简介
简单的说，Ribbon 是 Netflix 发布的开源项目，主要功能是提供客户端的软件负载均衡算法，将 Netflix 的中间层服务连接在一起。Ribbon 客户端组件提供一系列完善的配置项如连接超时，重试等。简单的说，就是在配置文件中列出Load Balancer（简称LB）后面所有的机器，Ribbon 会自动的帮助你基于某种规则（如简单轮询，随机连接等）去连接这些机器。我们也很容易使用 Ribbon 实现自定义的负载均衡算法。
RestTemplate的使用
RestTemplate是一个HTTP客户端，使用它我们可以方便的调用HTTP接口，支持GET、POST、PUT、DELETE等方法。
GET请求方法
T getForObject(String url, Class responseType, Object... uriVariables);
T getForObject(String url, Class responseType, Map uriVariables);
T getForObject(URI url, Class responseType);
ResponseEntitygetForEntity(String url, Class responseType, Object... uriVariables);
ResponseEntitygetForEntity(String url, Class responseType, Map uriVariables);
ResponseEntitygetForEntity(URI var1, Class responseType);
getForObject方法
@GetMapping("/{id}")
public CommonResultgetUser(@PathVariable Long id) {
return restTemplate.getForObject(userServiceUrl +"/user/{1}", CommonResult.class, id);
}
getForEntity方法
//返回对象为ResponseEntity对象，包含了响应中的一些重要信息，比如响应头、响应状态码、响应体等
@GetMapping("/getEntityByUsername")
public CommonResultgetEntityByUsername(@RequestParam String username) {
ResponseEntity entity = restTemplate.getForEntity(userServiceUrl +"/user/getByUsername?username={1}", CommonResult.class, username);
if (entity.getStatusCode().is2xxSuccessful()) {
return entity.getBody();
}else {
return new CommonResult("操作失败", 500);
}
}
POST请求方法
T postForObject(String url, @Nullable Object request, Class responseType, Object... uriVariables);
T postForObject(String url, @Nullable Object request, Class responseType, Map uriVariables);
T postForObject(URI url, @Nullable Object request, Class responseType);
ResponseEntitypostForEntity(String url, @Nullable Object request, Class responseType, Object... uriVariables);
ResponseEntitypostForEntity(String url, @Nullable Object request, Class responseType, Map uriVariables);
ResponseEntitypostForEntity(URI url, @Nullable Object request, Class responseType);
postForObject示例
@PostMapping("/create")
public CommonResultcreate(@RequestBody User user) {
return restTemplate.postForObject(userServiceUrl +"/user/create", user, CommonResult.class);
}
postForEntity示例
@PostMapping("/create")
public CommonResultcreate(@RequestBody User user) {
return restTemplate.postForEntity(userServiceUrl +"/user/create", user, CommonResult.class).getBody();
}
PUT请求方法
void put(String url, @Nullable Object request, Object... uriVariables);
void put(String url, @Nullable Object request, Map uriVariables);
void put(URI url, @Nullable Object request);
PUT请求示例
@PutMapping("/update")
public CommonResultupdate(@RequestBody User user) {
restTemplate.put(userServiceUrl +"/user/update", user);
return new CommonResult("操作成功",200);
}
DELETE请求方法
void delete(String url, Object... uriVariables);
void delete(String url, Map uriVariables);
void delete(URI url);
DELETE请求示例
@DeleteMapping("/delete/{id}")
public CommonResultdelete(@PathVariable Long id) {
restTemplate.delete(userServiceUrl +"/user/delete/{1}", null, id);
return new CommonResult("操作成功",200);
}
创建user-service模块
用来给ribbon提供服务，添加依赖
添加配置文件
server:
port:8201
spring:
application:
name: user-service
eureka:
client:
register-with-eureka: true
fetch-registry: true
service-url:
defaultZone: http://localhost:8001/eureka/
添加userController常用接口
package com.macro.cloud.controller;
import com.macro.cloud.domain.CommonResult;
import com.macro.cloud.domain.User;
import com.macro.cloud.service.UserService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
/**
* Created by danpipi.
*/
@RestController
@RequestMapping("/user")
public class UserController {
private LoggerLOGGER = LoggerFactory.getLogger(this.getClass());
@Autowired
private UserServiceuserService;
@PostMapping("/create")
public CommonResultcreate(@RequestBody User user) {
userService.create(user);
return new CommonResult("操作成功", 200);
}
@GetMapping("/{id}")
public CommonResultgetUser(@PathVariable Long id) {
User user =userService.getUser(id);
LOGGER.info("根据id获取用户信息，用户名称为：{}",user.getUsername());
return new CommonResult<>(user);
}
@GetMapping("/getUserByIds")
public CommonResult>getUserByIds(@RequestParam List ids) {
List userList=userService.getUserByIds(ids);
LOGGER.info("根据ids获取用户信息，用户列表为：{}",userList);
return new CommonResult<>(userList);
}
@GetMapping("/getByUsername")
public CommonResultgetByUsername(@RequestParam String username) {
User user =userService.getByUsername(username);
return new CommonResult<>(user);
}
@PostMapping("/update")
public CommonResultupdate(@RequestBody User user) {
userService.update(user);
return new CommonResult("操作成功", 200);
}
@PostMapping("/delete/{id}")
public CommonResultdelete(@PathVariable Long id) {
userService.delete(id);
return new CommonResult("操作成功", 200);
}
}
创建ribbon-service模块，调用user-service模块实现负载均衡，添加依赖
配置文件
server:
port:8301
spring:
application:
name: ribbon-serviceeureka:
client:
register-with-eureka:true
fetch-registry:true
service-url:
defaultZone: http://localhost:8001/eureka/
service-url:
user-service: http://user-service
@LoadBalanced注解可以提供RestTemplate负载均衡
package com.macro.cloud.config;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
/**
* Created by 蛋皮皮 on 2020/8/29.
*/
@Configuration
public class RibbonConfig {
@Bean
@LoadBalanced
public RestTemplaterestTemplate(){
return new RestTemplate();
}
}
UserRibbonController
package com.macro.cloud.controller;
import com.macro.cloud.domain.CommonResult;
import com.macro.cloud.domain.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.client.RestTemplate;
/**
* Created by 蛋皮皮 on 2020/8/29.
*/
@RestController
@RequestMapping("/user")
public class UserRibbonController {
@Autowired
private RestTemplaterestTemplate;
@Value("${service-url.user-service}")
private StringuserServiceUrl;
@GetMapping("/{id}")
public CommonResultgetUser(@PathVariable Long id) {
return restTemplate.getForObject(userServiceUrl +"/user/{1}", CommonResult.class, id);
}
@GetMapping("/getByUsername")
public CommonResultgetByUsername(@RequestParam String username) {
return restTemplate.getForObject(userServiceUrl +"/user/getByUsername?username={1}", CommonResult.class, username);
}
@GetMapping("/getEntityByUsername")
public CommonResultgetEntityByUsername(@RequestParam String username) {
ResponseEntity entity =restTemplate.getForEntity(userServiceUrl +"/user/getByUsername?username={1}", CommonResult.class, username);
if (entity.getStatusCode().is2xxSuccessful()) {
return entity.getBody();
}else {
return new CommonResult("操作失败", 500);
}
}
@PostMapping("/create")
public CommonResultcreate(@RequestBody User user) {
return restTemplate.postForObject(userServiceUrl +"/user/create", user, CommonResult.class);
}
@PostMapping("/update")
public CommonResultupdate(@RequestBody User user) {
return restTemplate.postForObject(userServiceUrl +"/user/update", user, CommonResult.class);
}
@PostMapping("/delete/{id}")
public CommonResultdelete(@PathVariable Long id) {
return restTemplate.postForObject(userServiceUrl +"/user/delete/{1}", null, CommonResult.class, id);
}
}
启动后调用接口测试http://localhost:8301/user/1
Ribbon的常用配置
#全局配置
ribbon:
ConnectTimeout: 1000 #服务请求连接超时时间（毫秒）
ReadTimeout: 3000 #服务请求处理超时时间（毫秒）
OkToRetryOnAllOperations: true #对超时请求启用重试机制
MaxAutoRetriesNextServer: 1 #切换重试实例的最大个数
MaxAutoRetries: 1 #切换实例后重试最大次数
NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule #修改负载均衡算法
指定服务配置
user-service:
ribbon:
ConnectTimeout: 1000 #服务请求连接超时时间（毫秒）
ReadTimeout: 3000 #服务请求处理超时时间（毫秒）
OkToRetryOnAllOperations: true #对超时请求启用重试机制
MaxAutoRetriesNextServer: 1 #切换重试实例的最大个数
MaxAutoRetries: 1 #切换实例后重试最大次数
NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule #修改负载均衡算法
使用到的模块
springcloud-learning
├── eureka-server -- eureka注册中心
├── user-service --提供User对象CRUD接口的服务
└── ribbon-service -- ribbon服务调用测试服务