1.什么内容协商
简单说就是服务提供方根据客户端所支持的格式来返回对应的报文,在 Spring 中,REST API 基本上都是以 json 格式进行返回,而如果需要一个接口即支持 json,又支持其他格式,开发和维护多套代码显然是不合理的,而 Spring 又恰好提供了该功能,那便是ContentNegotiation 在 Spring 中,决定一个数据是以 jso还是xml 分别如下:
favorPathExtension 后缀模式,例如:xxx.json,xxx.xml
favorParameter format模式,例如:xxx?format=json,xxx?format=xml,
通过请求的 Accept 来决定返回的值
2.代码工程
实验目标:根据请求参数不一样自动切换不同的格式的返回结果
pom.xml
<?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"><parent><artifactId>springboot-demo</artifactId><groupId>com.et</groupId><version>1.0-SNAPSHOT</version></parent><modelVersion>4.0.0</modelVersion><artifactId>ContentNegotiation</artifactId><properties><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-autoconfigure</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>com.fasterxml.jackson.dataformat</groupId><artifactId>jackson-dataformat-xml</artifactId></dependency></dependencies>
</project>
controller
package com.et.contentnegotiation.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;import java.util.HashMap;
import java.util.Map;
@Controller
public class HelloWorldController {@RequestMapping("/hello")@ResponseBodypublic Map<String, Object> showHelloWorld(){Map<String, Object> map = new HashMap<>();map.put("msg", "HelloWorld");return map;}
}
DemoApplication.java
package com.et.contentnegotiation;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication
public class DemoApplication {public static void main(String[] args) {SpringApplication.run(DemoApplication.class, args);}
}
application.yaml
server:port: 8088
spring:mvc:contentnegotiation:#favor-path-extension: true # header acceptfavor-parameter: true # url ?format=xml or format=jsonmedia-types:json: application/json
以上只是一些关键代码,所有代码请参见下面代码仓库
代码仓库
https://github.com/Harries/springboot-demo
3.测试
favorParameter 方式
设置配置文件里面参数
spring.mvc.contentnegotiation.favor-parameter=true
启动springboot应用,
http://127.0.0.1:8088/hello?format=xml
http://127.0.0.1:8088/hello?format=json
返回不同格式的结果
请求的 Accept 来决定返回的值
设置配置文件里面参数
spring.mvc.contentnegotiation.favor-path-extension=true
设置header里面Accept:application/xml 或者application/json
4.引用
http://www.liuhaihua.cn/archives/710402.html
https://segmentfault.com/a/1190000039805072