spring gateway使用基于netty异步io,第二代网关；
zuul 1使用servlet 3，第一代网关，每个请求一个线程，同步Servlet，多线程阻塞模型。
而spring貌似不想在支持zuul 2了

API网关作为后端服务的统一入口，可提供请求路由、协议转换、安全认证、服务鉴权、流量控制、日志监控等服务。

1.搭一个简单的网关

idea中file-new-project

pom.xml文件(引入eureka)

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>gatewaytest2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>gatewaytest2</name>
    <description>Demo project for Spring Boot</description>    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
    </properties>    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
    </dependencies>    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build></project>

applicaton.yml文件配置

spring:
  application:
    name: gateway8710
  cloud:
    gateway:
      default-filter:
      routes:
      - id: user-server
        predicates:
          - Path=/java/**
        filters:
          - StripPrefix=1
        uri: lb://service-helloword
        #  uri: "http://192.168.111.133:8708/project/hello"
server:
  port: 8710
eureka:
  client:
    serviceUrl:
      #指向注册中心
      defaultZone: http://192.168.111.133:8888/eureka/
  instance:
    # 每间隔1s，向服务端发送一次心跳，证明自己依然”存活“
    lease-renewal-interval-in-seconds: 1
    # 告诉服务端，如果我2s之内没有给你发心跳，就代表我“死”了，将我踢出掉。
    lease-expiration-duration-in-seconds: 2

注意：uri项中的lb第一个字母L的小写，配置这个表示要去eureka中查找相关的服务

StripPrefix=1表示去掉url中的前缀，如http://localhost:8710/java/project/hello,经过网关转后变成http://192.168.111.133:8708/project/hello,即去掉前缀/java,后面的不变，去注册中心找service-helloword服务的地址和端口

当配置uri使用绝对路径时写了项目路径（/project/hello）uri: “http://192.168.111.133:8708/project/hello”，不管请求的是路径是什么（http://localhost:8710/java/xxx/xxx）,都直接访问配置的地址http://192.168.111.133:8708/project/hello

当配置uri使用绝对路径时没写项目路径（/project/hello）如uri: “http://192.168.111.133:8708″，请求http://localhost:8710/java/xxx/xxx转发后变为http://192.168.111.133:8708/xxx/xxx

启动类Gatewaytest2Application.java

package com.example.gatewaytest2;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;@EnableEurekaClient
@SpringBootApplication
public class Gatewaytest2Application {    public static void main(String[] args) {
        SpringApplication.run(Gatewaytest2Application.class, args);
    }}

目录结构

2.启动测试

注册中心已经有我们的网关服务了

测试

返回

3.附service-helloword

controller

package com.pu.helloworld;import com.pu.common.ExcelUtil;
import com.pu.ioctest.IocTest;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;import javax.servlet.http.HttpServletResponse;
import java.io.OutputStream;
import java.net.URLEncoder;@RestController
@RequestMapping("/project")
public class helloController {
    private static Logger log = LoggerFactory.getLogger(helloController.class);    @RequestMapping(value = "/hello")
    //required=false 表示url中可以不传入id参数，此时就使用默认参数
    public String say(@RequestParam(value = "id", required = false, defaultValue = "hello world") String input) {
        log.debug("your input :" + input);
        return "your input :" + input;
    }
}