Spring Boot+Spring Cloud微服务案例演练（2）：Feign服务之间数据交互（上）

前言

Feign基于Netflix Feign实现，整合了Ribbon和Hystrix，Feign的功能包含了其他两者的功能。

此serverClientA工程是在Spring Boot+Spring Cloud微服务案例演练（1）：服务注册与发现步骤3中的基础上完成的。

一、搭建serverClientA服务工程

1.修改pom.xml配置文件，添加相关依赖

    
    
        org.springframework.cloud
        spring-cloud-starter-feign
        1.4.5.RELEASE
    

    
    
        org.thymeleaf
        thymeleaf
        3.0.9.RELEASE
    

    
        org.thymeleaf
        thymeleaf-spring4
        3.0.9.RELEASE
    

    
        org.springframework.boot
        spring-boot-starter-thymeleaf
    

2.修改application.properties配置文件

#启用Feign
feign.hystrix.enabled=true

#Thymeleaf配置
spring.thymeleaf.prefix=classpath:/templates/
spring.thymeleaf.suffix=.html
spring.thymeleaf.mode=HTML5
spring.thymeleaf.encoding=UTF-8
spring.thymeleaf.cache=false

在新版本中Feign对Hystrix的支持默认是关闭的，所以要通过配置手动打开feign.hystrix.enabled=true，这样服务降级等功能才有效果。

3.启动类中添加注解@EnableFeignClients

通过@EnableFeignClients来开启Spring Cloud的Feign支持功能。

package com.lpc.serverClientA;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients
public class ServerClientAApplication {

    public static void main(String[] args) {
        SpringApplication.run(ServerClientAApplication.class, args);
    }
}

4.新建MessageGenerationController类

该类负责将数据以xml报文的形式存储，并提供返回xml报文的方法供serverclientB调用。

package com.lpc.serverClientA.controller;

import com.lpc.serverClientA.entity.InputData;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import java.text.SimpleDateFormat;
import java.util.Date;

@Controller
public class MessageGenerationController {

    private String result, time;
    private Logger logger = LoggerFactory.getLogger(getClass());

    @RequestMapping(value = "/index", produces = "text/plain;charset=UTF-8")
    public String index(ModelMap map) {

        InputData inputData = new InputData();
        time = getDate();

        inputData.setDate(time);
        map.put("fpInfo", inputData);
        return "index";
    }

    @ResponseBody
    @RequestMapping(value = "/generateXML", method = RequestMethod.POST, produces = "text/plain;charset=UTF-8")
    private String generate(@ModelAttribute InputData inputData) {

        logger.info("inputData = " + inputData.toString());
        result = rtnXML(inputData);
        return "result = " + result;
    }

    //生成xml报文
    private String rtnXML(InputData inputData) {

        Document document = DocumentHelper.createDocument();
        document.setXMLEncoding("utf-8");
        Element root = document.addElement("FPXT");//添加根节点
        Element output = root.addElement("OUTPUT");

        Element fpzl = output.addElement("FPZL");
        fpzl.addText(inputData.getFpzl());

        Element fpzt = output.addElement("FPZT");
        fpzt.addText(inputData.getFpzt());

        Element nsrsbh = output.addElement("NSRSBH");
        nsrsbh.addText(inputData.getNsrsbh());

        Element date = output.addElement("DATE");
        date.addText(time);

        Element fpdm = output.addElement("FPDM");
        fpdm.addText(inputData.getFpdm());

        String resultXML = document.asXML();
        logger.debug("resultXML = " + resultXML);
        return resultXML;
    }

    //获取当前时间
    private String getDate() {

        Date date = new Date();
        SimpleDateFormat simpleDate = new SimpleDateFormat("yyyy-MM-dd kk:mm:ss");
        return simpleDate.format(date);
    }

    //返回xml报文，供serverClientB服务调用
    @RequestMapping(value = "/generate", method = RequestMethod.GET)
    public ResponseEntity