前面已经在平台中使用了spring cloud。每个小的服务中各自实现相关业务，提供API。这些服务的访问地址都可能不一样。这样给使用都造成困扰，而且服务器接口管理也复杂了。
api-gateway就是把这些api通过一个服务提供出去。在这个服务中代理其它服务的API。对于服务的使用都就像是访问一台服务器。
这里用spring zuul实现api-gateway。

创建项目

创建一个项目（服务），专门做api代理。服务名称huip-router。

项目结构

pom

<?xml version="1.0"?>
<project
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
    xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>com.biboheart</groupId>
        <artifactId>huip</artifactId>
        <version>1.0.1-SNAPSHOT</version>
    </parent>

    <artifactId>huip-router</artifactId>
    <name>huip-router</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <maimClass>com.biboheart.huip.router.RouterApplication</maimClass>
                    <executable>true</executable>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

RouterApplication

package com.biboheart.huip.router;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

@SpringBootApplication
@EnableZuulProxy
public class RouterApplication {
    public static void main(String[] args) {
        SpringApplication.run(RouterApplication.class, args);
    }
}

为了支持跨域，增加一个Filter

package com.biboheart.huip.router.filters;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class CorsFilter implements Filter {

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
            throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;
        response.setHeader("Access-Control-Allow-Credentials", "true");
        response.setHeader("Access-Control-Allow-Origin", request.getHeader("Origin"));
        response.setHeader("Access-Control-Allow-Methods", "POST, PUT, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Allow-Headers", "X-Auth-Token, x-csrf-token, X-XSRF-TOKEN, X-Token, Origin, X-Requested-With, Content-Type, Accept, Authorization, access_secret, access_token");
        response.setHeader("Access-Control-Max-Age", "3600");
        if(!request.getMethod().equals("OPTIONS")) {
            chain.doFilter(req, res);
        }
    }

    @Override
    public void destroy() {}

    @Override
    public void init(FilterConfig arg0) throws ServletException {}

}

配置

server:
  # 服务端口号
  port: 8080
  
spring:
  mvc:
    favicon:
      enabled: false
  output:
    ansi:
      enabled: DETECT
  http:
    encoding:
      charset: UTF-8
    multipart:
      maxFileSize: -1
      maxRequestSize: 500MB

zuul:
  addProxyHeaders: true
  host:
    socket-timeout-millis: 600000
    connect-timeout-millis: 600000
  routes:
    ########## 用户服务(user) ##########
    user-service:
      path: /huipuser/**
      sensitiveHeaders: 
      serviceId: huip-user-server
      stripPrefix: true
    patient-service:
      path: /huippatient/**
      sensitiveHeaders: 
      serviceId: huip-patient-server
      stripPrefix: true
      
hystrix:
  command:
    myusers-service:
      execution:
        timeout:
          enabled: false
        isolation:
          thread:
            timeoutInMilliseconds: 600000
            
ribbon:
  ConnectTimeout: 3000
  ReadTimeout: 60000
  eureka:
    enabled: true

# LOGGING
logging:
  level:
    root: info
    

在API请求开头为/huipuser/时访问的是user服务的API，如果开头/huippatient/时访问的是patient服务的API。比如请求http://localhost:8080/huippatient/loadUser相当于http://localhost:8280/loadUser
请求测试。
SpringBoot实例:医院统一信息平台(服务间通讯)的访问流程改成用代理。

直接访问

代理访问

直接访问

代理访问