SpringCloud——接口互相調用(RestTemplate+Ribbon)

我之前寫過兩個接口服務user和student，現在將它完善一下

user，創建一個接口 localhost:12003/getUserList 返回一個json數據，用來做測試

UserApi.java

package com.springcloud.demo.api;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.springcloud.demo.domain.BaseJSON;
import com.springcloud.demo.domain.po.UserPO;
import com.springcloud.demo.server.UserService;

@RestController
public class UserApi {
	
	@Autowired
	public UserService userService;
	
	@RequestMapping(value="/test",method=RequestMethod.GET)
	public String test() {
		return "Hello World";
	}
	
	@RequestMapping(value="/getUserList",method=RequestMethod.GET)
	public BaseJSON getUserList() {
		BaseJSON json = new BaseJSON();
		List<UserPO> list = userService.getUserList();
		if(list.size()<0||list==null) {
			json.setCode(11);
			json.setMessage("失敗");
		}else {
			json.setResult(list);
		}
		return json;
	}
	
}

Service層實現

package com.springcloud.demo.server.imp;

import java.util.ArrayList;
import java.util.List;

import org.springframework.stereotype.Service;

import com.springcloud.demo.domain.po.UserPO;
import com.springcloud.demo.server.UserService;

@Service
public class UserServiceImp implements UserService{

	@Override
	public List<UserPO> getUserList() {
		List<UserPO> list = new ArrayList<>();
		UserPO user = new UserPO();
		
		user.setId(1);
		user.setUsername("lg");
		user.setPassword("123456");
		list.add(user);
		
		user.setId(2);
		user.setUsername("lxy");
		user.setPassword("123456");
		list.add(user);
		return list;
	}

	
}

Student 調用 user的restFul接口，獲取數據，然後將數據重新封裝

首先我們需要注入RestTemplate，這裏我們圖方便加載BootMain中了，使用@LoadBalanced註解標明

package com.springcloud.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;
import org.springframework.context.annotation.Bean;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.client.RestTemplate;

import springfox.documentation.annotations.ApiIgnore;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

@Controller
@SpringBootApplication
@ApiIgnore
@EnableScheduling 
@EnableDiscoveryClient
@EnableFeignClients
@EnableSwagger2
@EnableHystrixDashboard
public class BootMain {
	public static void main(String[] args) {
		SpringApplication.run(BootMain.class, args);
	}
	
	@RequestMapping("/help")
	public String help() {
		return "redirect:swagger-ui.html";
	}
	/**
    重點看這裏
    */
	@Bean
    @LoadBalanced
    RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

service調用實現

【注】：

1、RestTemplate 訪問的URL不能攜帶ip和端口號，不然會報錯,改成你所調用的服務在註冊中心註冊的名字

報錯 
No instances available for 192.168.xx.xx
No instances available for [IP]

2、使用Entity接收RestTemplate獲取到的值

@Autowired 
private RestTemplate rt;

//ResponseEntity<BaseJSON> re = rt.getForEntity(url, BaseJSON.class);
HttpEntity<BaseJSON> re = rt.getForEntity(url, BaseJSON.class);
BaseJSON json = re.getBody();

獲取到的json就是我門的目標json對象（BaseJSON自己封裝的），裏面擁有從user獲取到的全部數據
3、在獲取對象時候，我們得到的Object無法直接轉爲目標對象StudentPO，我們可以先將其轉爲json字符串，然後再轉爲我們的目標對象，需要在pom.xml中加入jar包，具體java<——>操作可見：json數據對象操作

<dependency>
			<groupId>net.sf.json-lib</groupId>
			<artifactId>json-lib</artifactId>
			<version>2.4</version>
			<classifier>jdk15</classifier>
		</dependency>

package com.springcloud.demo.service.imp;

import java.util.ArrayList;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpEntity;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

import com.springcloud.demo.domain.BaseJSON;
import com.springcloud.demo.domain.po.StudentPO;
import com.springcloud.demo.domain.po.UserPO;
import com.springcloud.demo.service.StudentService;

import net.sf.json.JSONObject;

@Service
public class StudentServiceImp implements StudentService{
	
	@Autowired 
	private RestTemplate rt;
	
	@Override
	public List<StudentPO> getStudentList() {
		//使用RestTemplate
		String url = "http://user/getUserList";
		/**
		 * String url = "http://192.168.99.115:12001/user/getUserList";
		  * 報錯：No instances available for [IP]
		 */
		//ResponseEntity<BaseJSON> re = rt.getForEntity(url, BaseJSON.class);
		HttpEntity<BaseJSON> re = rt.getForEntity(url, BaseJSON.class);
		BaseJSON json = re.getBody();
		
		List<UserPO> userList = new ArrayList();
		List<StudentPO> studentList = new ArrayList();
		
		if(json.getCode()==0) {
			userList = (List<UserPO>) json.getResult();
			for(Object obj:userList) {
				JSONObject jsonObject = JSONObject.fromObject(obj);
				
				UserPO user = (UserPO)jsonObject.toBean(jsonObject,UserPO.class);
				StudentPO student = new StudentPO();
				student.setId(user.getId());
				student.setName(user.getUsername());
				student.setPassword(user.getUsername());
				student.setGrade(1);
				studentList.add(student);
			}
		}else {
			studentList = null;
		}
		return studentList;
	}
	
}