百度360必应搜狗淘宝本站头条
java配置环境变量fill_parent函数指针百度网盘下载速度慢破解方法谷歌浏览器免费入口
当前位置：网站首页 > 技术流 > 正文

spring4.1.8扩展实战之一:自定义环境变量验证

citgpt 2024-07-12 09:59 12 浏览 0 评论

关于扩展

  • 在之前学习spring环境初始化源码的过程中，见到有些地方能通过子类来实现自定义扩展，从本章开始，我们来逐个实践这些扩展，除了加深对spring的理解，有的扩展也能解决一些通用的问题；
  • 文中涉及的spring版本号为4.1.8.RELEASE；

扩展功能介绍

spring4.1.8扩展实战之一:自定义环境变量验证

  • 今天实战的内容，是通过spring容器来确保环境变量MYSQL_HOST一定存在，如果不存在应用就会启动失败；

分析spring源码

  • 通过分析spring源码来确定如何扩展；
  • 在spring环境初始化的时候，AbstractApplicationContext的prepareRefresh方法会被调用，源码如下
protected void prepareRefresh() {
		this.startupDate = System.currentTimeMillis();
		this.closed.set(false);
		this.active.set(true);

		if (logger.isInfoEnabled()) {
			logger.info("Refreshing " + this);
		}

		// Initialize any placeholder property sources in the context environment
		initPropertySources();

		// Validate that all properties marked as required are resolvable
		// see ConfigurablePropertyResolver#setRequiredProperties
		getEnvironment().validateRequiredProperties();
	}
  • initPropertySources是个空方法，留给子类扩展；
  • 来看看getEnvironment().validateRequiredProperties()的源码，对应的是AbstractPropertyResolver类的validateRequiredProperties方法：
public void validateRequiredProperties() {
		MissingRequiredPropertiesException ex = new MissingRequiredPropertiesException();
		for (String key : this.requiredProperties) {
			if (this.getProperty(key) == null) {
				ex.addMissingRequiredProperty(key);
			}
		}
		if (!ex.getMissingRequiredProperties().isEmpty()) {
			throw ex;
		}
	}
  • 可见spring容器初始化的时候，会从集合requiredProperties中取出所有key，然后获取这些key的环境变量（包括系统环境变量和进程环境变量），如果有一个key对应的环境变量为空，就会抛出异常，导致spring容器初始化失败；

扩展功能分析

  • 看了AbstractPropertyResolver类的validateRequiredProperties方法源码后，可以确定该方法能强制要求一些环境变量必须存在，否则停止spring启动，我们只要把我们认为必要的环境变量的key存入集合requiredProperties中即可，达到此目标需要解决下面两个问题：
  • 如何将环境变量的key存入集合requiredProperties？

调用AbstractPropertyResolver类的setRequiredProperties方法，注意该方法是向集合requiredProperties中添加数据，并不会将已有数据清除；

  • 在什么时候执行AbstractPropertyResolver类的setRequiredProperties方法设置key？

创建一个AbstractApplicationContext的子类，重写initPropertySources方法，在此方法中执行AbstractPropertyResolver类的setRequiredProperties；

开始实战

  • 用maven创建一个SpringBoot工程，工程名为customizepropertyverify，pom.xml内容如下：
<?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>

    <groupId>com.bolingcavalry</groupId>
    <artifactId>customizepropertyverify</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>customizepropertyverify</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <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>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>
  • 创建一个类CustomApplicationContext，继承自AnnotationConfigServletWebServerApplicationContext，重写initPropertySources方法，将"MYSQL_HOST"作为启动时必须要存在的环境变量：
package com.bolingcavalry.customizepropertyverify.context;

import org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext;

/**
 * @Description : AnnotationConfigServletWebServerApplicationContext，重写了initPropertySources方法，
 * 要求spring启动的时候环境变量MYSQL_HOST必须存在
 * @Author : zq2599@gmail.com
 * @Date : 2018-08-10 21:40
 */
public class CustomApplicationContext extends AnnotationConfigServletWebServerApplicationContext {

    @Override
    protected void initPropertySources() {
        super.initPropertySources();
        //把"MYSQL_HOST"作为启动的时候必须验证的环境变量
        getEnvironment().setRequiredProperties("MYSQL_HOST");
    }
}
  • 创建应用启动类CustomizepropertyverifyApplication，指定ApplicationContext的class为CustomApplicationContext：
package com.bolingcavalry.customizepropertyverify;

import com.bolingcavalry.customizepropertyverify.context.CustomApplicationContext;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class CustomizepropertyverifyApplication {

    public static void main(String[] args) {
        SpringApplication springApplication = new SpringApplication(CustomizepropertyverifyApplication.class);
        springApplication.setApplicationContextClass(CustomApplicationContext.class);
        springApplication.run(args);
    }
}
  • 打包，在pom.xml文件所在目录下执行命令mvn clean package -U -DskipTests，命令执行完成后，即可在target目录找到文件customizepropertyverify-0.0.1-SNAPSHOT.jar；

实战源码下载

  • 本章实战的源码可以在github下载，地址和链接信息如下表所示：
  • 这个git项目中有多个文件夹，本章源码在文件夹customizepropertyverify下，如下图红框所示：

验证

  • 接下来我们来验证自定义的ApplicationContext是否实现了环境变量检查的功能；
  • “MYSQL_HOST"这个环境变量是不存在的，所以我们先验证环境变量校验不通过导致spring容器启动失败的情况，在target目录执行命令java -jar customizepropertyverify-0.0.1-SNAPSHOT.jar，会发现应用启动失败，日志中显示由于找不到环境变量"MYSQL_HOST”，在AbstractPropertyResolver.validateRequiredProperties位置抛出异常，如下所示：
D:\github\blog_demos\customizepropertyverify\target>java -jar customizepropertyverify-0.0.1-SNAPSHOT.jar

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.0.4.RELEASE)

2018-08-12 14:10:16.165  INFO 19624 --- [           main] c.b.c.CustomizepropertyverifyApplication : Starting CustomizepropertyverifyApplication v0.0.1-SNAPSHOT on DESKTOP-82CCEBN with PID 19624 (D:\github\blog_demos\customizepropertyverify\target\customizepropertyverify-0.0.1-SNAPSHOT.jar started by 12167 in D:\github\blog_demos\customizepropertyverify\target)
2018-08-12 14:10:16.168  INFO 19624 --- [           main] c.b.c.CustomizepropertyverifyApplication : No active profile set, falling back to default profiles: default
2018-08-12 14:10:16.218  INFO 19624 --- [           main] c.b.c.context.CustomApplicationContext   : Refreshing com.bolingcavalry.customizepropertyverify.context.CustomApplicationContext@6d1e7682: startup date [Sun Aug 12 14:10:16 GMT+08:00 2018]; root of context hierarchy
2018-08-12 14:10:16.221  WARN 19624 --- [           main] o.s.boot.SpringApplication               : Error handling failed (ApplicationEventMulticaster not initialized - call 'refresh' before multicasting events via the context: com.bolingcavalry.customizepropertyverify.context.CustomApplicationContext@6d1e7682: startup date [Sun Aug 12 14:10:16 GMT+08:00 2018]; root of context hierarchy)
2018-08-12 14:10:16.226 ERROR 19624 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.core.env.MissingRequiredPropertiesException: The following properties were declared as required but could not be resolved: [MYSQL_HOST]
        at org.springframework.core.env.AbstractPropertyResolver.validateRequiredProperties(AbstractPropertyResolver.java:146) ~[spring-core-5.0.8.RELEASE.jar!/:5.0.8.RELEASE]
        at org.springframework.core.env.AbstractEnvironment.validateRequiredProperties(AbstractEnvironment.java:519) ~[spring-core-5.0.8.RELEASE.jar!/:5.0.8.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.prepareRefresh(AbstractApplicationContext.java:598) ~[spring-context-5.0.8.RELEASE.jar!/:5.0.8.RELEASE]
        at org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext.prepareRefresh(AnnotationConfigServletWebServerApplicationContext.java:200) ~[spring-boot-2.0.4.RELEASE.jar!/:2.0.4.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:519) ~[spring-context-5.0.8.RELEASE.jar!/:5.0.8.RELEASE]
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.4.RELEASE.jar!/:2.0.4.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:762) ~[spring-boot-2.0.4.RELEASE.jar!/:2.0.4.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:398) ~[spring-boot-2.0.4.RELEASE.jar!/:2.0.4.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:330) ~[spring-boot-2.0.4.RELEASE.jar!/:2.0.4.RELEASE]
        at com.bolingcavalry.customizepropertyverify.CustomizepropertyverifyApplication.main(CustomizepropertyverifyApplication.java:13) [classes!/:0.0.1-SNAPSHOT]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_181]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_181]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_181]
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) [customizepropertyverify-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) [customizepropertyverify-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) [customizepropertyverify-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) [customizepropertyverify-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT]
...
  • 接下来验证环境变量"MYSQL_HOST"存在的时候应用是否能初始化成功，执行命令java -DMYSQL_HOST=“192.168.0.1” -jar customizepropertyverify-0.0.1-SNAPSHOT.jar，这个命令可以将"MYSQL_HOST"设置到进程环境变量中，这次顺利通过校验，应用启动成功：
D:\github\blog_demos\customizepropertyverify\target>java -DMYSQL_HOST="192.168.0.1" -jar customizepropertyverify-0.0.1-SNAPSHOT.jar

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.0.4.RELEASE)

2018-08-12 14:15:31.811  INFO 15328 --- [           main] c.b.c.CustomizepropertyverifyApplication : Starting CustomizepropertyverifyApplication v0.0.1-SNAPSHOT on DESKTOP-82CCEBN with PID 15328 (D:\github\blog_demos\customizepropertyverify\target\customizepropertyverify-0.0.1-SNAPSHOT.jar started by 12167 in D:\github\blog_demos\customizepropertyverify\target)
2018-08-12 14:15:31.813  INFO 15328 --- [           main] c.b.c.CustomizepropertyverifyApplication : No active profile set, falling back to default profiles: default
2018-08-12 14:15:31.850  INFO 15328 --- [           main] c.b.c.context.CustomApplicationContext   : Refreshing com.bolingcavalry.customizepropertyverify.context.CustomApplicationContext@3339ad8e: startup date [Sun Aug 12 14:15:31 GMT+08:00 2018]; root of context hierarchy
2018-08-12 14:15:32.776  INFO 15328 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2018-08-12 14:15:32.796  INFO 15328 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2018-08-12 14:15:32.796  INFO 15328 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.32
2018-08-12 14:15:32.805  INFO 15328 --- [ost-startStop-1] o.a.catalina.core.AprLifecycleListener   : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\iCLS\;C:\Program Files\Intel\Intel(R) Management Engine Components\iCLS\;C:\windows\system32;C:\windows;C:\windows\System32\Wbem;C:\windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\jdk\bin;C:\software\Git\cmd;C:\software\apache-maven-3.5.0\bin;;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;%SYSTEMROOT%\System32\OpenSSH\;C:\Users\12167\AppData\Local\Microsoft\WindowsApps;;.]
2018-08-12 14:15:32.867  INFO 15328 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2018-08-12 14:15:32.868  INFO 15328 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1021 ms
2018-08-12 14:15:32.919  INFO 15328 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Servlet dispatcherServlet mapped to [/]
2018-08-12 14:15:32.923  INFO 15328 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-08-12 14:15:32.923  INFO 15328 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-08-12 14:15:32.926  INFO 15328 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-08-12 14:15:32.927  INFO 15328 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2018-08-12 14:15:33.006  INFO 15328 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-08-12 14:15:33.136  INFO 15328 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: com.bolingcavalry.customizepropertyverify.context.CustomApplicationContext@3339ad8e: startup date [Sun Aug 12 14:15:31 GMT+08:00 2018]; root of context hierarchy
2018-08-12 14:15:33.190  INFO 15328 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/hello]}" onto public java.lang.String com.bolingcavalry.customizepropertyverify.controller.HelloWorldController.hello()
2018-08-12 14:15:33.194  INFO 15328 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2018-08-12 14:15:33.195  INFO 15328 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-08-12 14:15:33.226  INFO 15328 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-08-12 14:15:33.227  INFO 15328 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-08-12 14:15:33.314  INFO 15328 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2018-08-12 14:15:33.343  INFO 15328 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2018-08-12 14:15:33.346  INFO 15328 --- [           main] c.b.c.CustomizepropertyverifyApplication : Started CustomizepropertyverifyApplication in 1.761 seconds (JVM running for 2.113)
2018-08-12 14:15:39.626  INFO 15328 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
2018-08-12 14:15:39.626  INFO 15328 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2018-08-12 14:15:39.645  INFO 15328 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 16 ms
  • 验证完成，我们可以通过自定义子类来强制要求指定的环境变量必须存在；
  • 至此，我们spring扩展实战的第一章就结束了，接下来的章节我们会进行更多的实战，来了解spring强大的扩展机制；

相关推荐

js中arguments详解

一、简介了解arguments这个对象之前先来认识一下javascript的一些功能：其实Javascript并没有重载函数的功能，但是Arguments对象能够模拟重载。Javascrip中每个函数...

firewall-cmd 常用命令

目录firewalldzone说明firewallzone内容说明firewall-cmd常用参数firewall-cmd常用命令常用命令 回到顶部firewalldzone...

epel-release 是什么

EPEL-release（ExtraPackagesforEnterpriseLinux）是一个软件仓库，它为企业级Linux发行版（如CentOS、RHEL等）提供额外的软件包。以下是关于E...

FullGC详解 什么是 JVM 的 GC
FullGC详解 什么是 JVM 的 GC

前言：背景：一、什么是JVM的GC?JVM（JavaVirtualMachine）。JVM是Java程序的虚拟机，是一种实现Java语言的解...

2024-10-26 08:50 citgpt

使用Spire.Doc组件利用模板导出Word文档
  • 使用Spire.Doc组件利用模板导出Word文档
  • 使用Spire.Doc组件利用模板导出Word文档
  • 使用Spire.Doc组件利用模板导出Word文档
  • 使用Spire.Doc组件利用模板导出Word文档
跨域（CrossOrigin）

1.介绍　　1)跨域问题：跨域问题是在网络中，当一个网络的运行脚本（通常时JavaScript）试图访问另一个网络的资源时，如果这两个网络的端口、协议和域名不一致时就会出现跨域问题。　　　　通俗讲...

微服务架构和分布式架构的区别

1、含义不同微服务架构：微服务架构风格是一种将一个单一应用程序开发为一组小型服务的方法，每个服务运行在自己的进程中，服务间通信采用轻量级通信机制(通常用HTTP资源API)。这些服务围绕业务能力构建并...

深入理解与应用CSS clip-path 属性
深入理解与应用CSS clip-path 属性

clip-pathclip-path是什么clip-path 是一个CSS属性，允许开发者创建一个剪切区域，从而决定元素的哪些部分可见，哪些部分会被隐...

2024-10-25 11:51 citgpt

HCNP Routing&Switching之OSPF LSA类型（二）
  • HCNP Routing&Switching之OSPF LSA类型（二）
  • HCNP Routing&Switching之OSPF LSA类型（二）
  • HCNP Routing&Switching之OSPF LSA类型（二）
  • HCNP Routing&Switching之OSPF LSA类型（二）
Redis和Memcached的区别详解
  • Redis和Memcached的区别详解
  • Redis和Memcached的区别详解
  • Redis和Memcached的区别详解
  • Redis和Memcached的区别详解
Request.ServerVariables 大全

Request.ServerVariables("Url")返回服务器地址Request.ServerVariables("Path_Info")客户端提供的路...

python操作Kafka

目录一、python操作kafka1.python使用kafka生产者2.python使用kafka消费者3.使用docker中的kafka二、python操作kafka细...

Runtime.getRuntime().exec详解

Runtime.getRuntime().exec详解概述Runtime.getRuntime().exec用于调用外部可执行程序或系统命令，并重定向外部程序的标准输入、标准输出和标准错误到缓冲池。...

promise.all详解 promise.all是干什么的
promise.all详解 promise.all是干什么的

promise.all详解promise.all中所有的请求成功了，走.then()，在.then()中能得到一个数组，数组中是每个请求resolve抛出的结果...

2024-10-24 16:21 citgpt

Content-Length和Transfer-Encoding详解
  • Content-Length和Transfer-Encoding详解
  • Content-Length和Transfer-Encoding详解
  • Content-Length和Transfer-Encoding详解
  • Content-Length和Transfer-Encoding详解

取消回复欢迎 你 发表评论:

一周热门
最近发表
标签列表
本站资源收集于网络以及网友投稿，其版权归原创者所有，如有侵害到你的权益，或有不妥之处，
请联系jellybean52032@gmail.com，提供原文链接地址以及资料原创证明，本站将会立即删除。