SpringCloud Gateway 是 SpringCloud 官方推出的第二代網關框架(第一代:Zuul),網關的常見功能:路由轉發、權限校驗和流量控制。
1. 網關工程
使用 RouteLocatorBuilder 的 bean 去創建路由,RouteLocatorBuilder 中可以添加各種 Predicate 和 Filter:
- Predicate :斷言,路由轉發的判斷條件;
- Filter :過濾器,路由請求時所經過的過濾邏輯,可用於修改請求、響應內容;
網關工程目錄如下圖所示:
pom.xml 如下所示,引入了 spring-cloud-starter-gateway 的依賴:
<?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 https://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>2.2.4.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.syrdbt</groupId>
<artifactId>study</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>study</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-cloud.version>Hoxton.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>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</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>
啓動類,GatewaStudyApplication.java ,使用 RouteLocator 進行路由轉發,轉發到下游業務,下游業務的地址爲 http://localhost:8081 ,本網關項目的端口號爲默認的 8080;斷言用來判斷,如果訪問路徑爲/hello則進行過濾和轉發,過濾器給轉發的請求增加了一個header,header 的 key 爲 Hello ,value 爲 World。
package com.syrdbt.study;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.gateway.route.RouteLocator;
import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.http.HttpHeaders;
import org.springframework.util.RouteMatcher;
import org.springframework.web.bind.annotation.RequestHeader;
@SpringBootApplication
public class GatewaStudyApplication {
public static void main(String[] args) {
SpringApplication.run(GatewaStudyApplication.class, args);
}
@Bean
public RouteLocator myRoutes(RouteLocatorBuilder builder) {
return builder.routes().route(p -> p
// 斷言,路由轉發的判斷條件,path 爲使用過濾器修改 /hello
.path("/hello")
// 過濾器,路由請求時所經過的過濾邏輯,可用於修改請求、響應內容;
.filters(f -> f.addRequestHeader("Hello", "World"))
.uri("http://localhost:8081"))
.build();
}
}
2. Web 工程,網關的下游業務
網關的下游業務 admin-web,工程目錄如下圖所示:
pom.xml 如下所示,引入了 spring-boot-starter-web :
<?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 https://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>2.2.5.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.syrdbt</groupId>
<artifactId>admin</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>admin</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
控制器,響應從網關發過來的請求,並打印了請求中key爲Hello的Header,HelloController.java:
package com.syrdbt.admin.controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.servlet.http.HttpServletRequest;
/**
* @author syrdbt
* @date 2020-03-03
*/
@RestController
public class HelloController {
/**
* 響應從網關發過來的請求,並打印了請求中key爲Hello的Header
*/
@RequestMapping("/hello")
public String hello(HttpServletRequest request) {
return "轉發成功。請求頭Hello的值" + request.getHeader("Hello");
}
}
啓動類,正常創建即可,不過需要修改一下工程的端口號爲 8081,application.properties 如下所示 :
server.port=8081
2.3 測試
訪問 http://localhost:8080/hello,請求被轉發到 http://localhost:8081/hello 。
訪問 http://localhost:8080/hello1,因爲不符合斷言,無法進行轉發,所以 404 找不到對應的頁面。