(转载请注明来源:cnblogs coder-fang)
本实例包括Nacos服务发现,配置中心,sentinel 容断简单使用,Spring cloud alibaba 的dubbo实例及所有服务的docker部署。
<?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>spcloud-dubbo</groupId> <artifactId>demo-api</artifactId> <version>1.0</version> <!-- 发布到仓库 --> <distributionManagement> <repository> <id>nexus-releases</id> <name>Nexus Release Repository</name> <url>http://nexusserver:6060/nexus/content/repositories/releases/</url> </repository> <snapshotRepository> <id>nexus-snapshots</id> <name>Nexus Snapshot Repository</name> <url>http://nexusserver:6060/nexus/content/repositories/snapshots/</url> </snapshotRepository> </distributionManagement> </project>
package spcloud.demoapi; public interface IApiService { String Hello(String name); }
<?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>2.2.7.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.spcouddubbo.demo</groupId> <artifactId>provider</artifactId> <version>1.0</version> <name>provider</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> <spring-cloud-alibaba.version>2.2.1.RELEASE</spring-cloud-alibaba.version> </properties> <dependencies> <dependency> <groupId>spcloud-dubbo</groupId> <artifactId>demo-api</artifactId> <version>1.0</version> </dependency> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId> </dependency> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-dubbo</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>com.alibaba.cloud</groupId> <artifactId>spring-cloud-alibaba-dependencies</artifactId> <version>${spring-cloud-alibaba.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
spring:
application:
name: provider
main:
allow-bean-definition-overriding: true
cloud:
nacos:
discovery:
enabled: true
register-enabled: true
server-addr: nacosserver:8848
config:
server-addr: nacosserver:8848
dubbo:
scan:
base-packages: com.spcouddubbo.demo.provider
protocols:
dubbo:
name: dubbo
port: -1
cloud:
subscribed-services:
demo:
user: nouser
package com.spcouddubbo.demo.provider; import com.alibaba.nacos.api.config.annotation.NacosValue; import org.apache.dubbo.config.annotation.Service; import org.springframework.beans.factory.annotation.Value; import org.springframework.cloud.client.loadbalancer.LoadBalanced; import org.springframework.cloud.context.config.annotation.RefreshScope; import spcloud.demoapi.IApiService; @Service @RefreshScope public class APIImplment implements IApiService { @Value("${demo.user}") String user; @Override public String Hello(String s) { return "hello 1 "+s+" "+user; } }
<?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>2.2.7.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.spclouddubbo.demo</groupId> <artifactId>consumer</artifactId> <version>1.0</version> <name>consumer</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> <spring-cloud-alibaba.version>2.2.1.RELEASE</spring-cloud-alibaba.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId> </dependency> <dependency> <groupId>spcloud-dubbo</groupId> <artifactId>demo-api</artifactId> <version>1.0</version> </dependency> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-dubbo</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>com.alibaba.cloud</groupId> <artifactId>spring-cloud-alibaba-dependencies</artifactId> <version>${spring-cloud-alibaba.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>
spring:
application:
name: comsumer
main:
allow-bean-definition-overriding: true
cloud:
nacos:
discovery:
enabled: true
register-enabled: true
server-addr: nacosserver:8848
config:
server-addr: nacosserver:8848
dubbo:
cloud:
subscribed-services: provider
consumer:
check: false
package com.spclouddubbo.demo.consumer; import com.alibaba.csp.sentinel.annotation.SentinelResource; import com.alibaba.csp.sentinel.slots.block.BlockException; import org.apache.dubbo.config.annotation.Reference; import org.apache.dubbo.rpc.RpcException; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.web.bind.annotation.*; import spcloud.demoapi.IApiService; @SpringBootApplication @RestController @EnableDiscoveryClient public class ConsumerApplication { public static void main(String[] args) { SpringApplication.run(ConsumerApplication.class, args); } @Reference IApiService service; @ResponseBody @GetMapping("/") @SentinelResource(fallbackClass = ProviderError.class,defaultFallback = "errorService") public String Getname( String name) { return service.Hello(name); } }
package com.spclouddubbo.demo.consumer; public class ProviderError { public static String errorService() { return "Call Provider services error"; } }
version: "3.1"
services:
db:
image: mysql:5.6
restart: always
container_name: nacosdb
hostname: nacosdb
volumes:
- ./mysql:/var/lib/mysql
networks:
- localnet
nacos:
image: nacos/nacos-server
container_name: nacos-standalone-mysql
hostname: nacoshost
env_file:
- ./mysql.env
volumes:
- ./logs/:/home/nacos/logs
- ./custom.properties:/home/nacos/init.d/custom.properties
ports:
- "8848:8848"
- "9555:9555"
restart: "no"
depends_on:
- db
networks:
- localnet
links:
- db
networks:
localnet:
external: true
mysql.env
MYSQL_SERVICE_DB_NAME=nacos
MYSQL_SERVICE_USER=nacos
MYSQL_SERVICE_PASSWORD=nacos
MYSQL_SERVICE_PORT=3306
MYSQL_SERVICE_HOST=db
MODE=standalone
custom.properties 根据需求自行配置
#spring.security.enabled=false
#management.security=false
#security.basic.enabled=false
#nacos.security.ignore.urls=/**
#management.metrics.export.elastic.host=http://localhost:9200
# metrics for prometheus
management.endpoints.web.exposure.include=*
# metrics for elastic search
#management.metrics.export.elastic.enabled=false
#management.metrics.export.elastic.host=http://localhost:9200
# metrics for influx
#management.metrics.export.influx.enabled=false
#management.metrics.export.influx.db=springboot
#management.metrics.export.influx.uri=http://localhost:8086
#management.metrics.export.influx.auto-create-db=true
#management.metrics.export.influx.consistency=one
#management.metrics.export.influx.compressed=true
可先启动mysql 进行用户nacos创建与脚本初始化,脚本代码 Git链接:
/******************************************/ /* 数据库全名 = nacos_config */ /* 表名称 = config_info */ /******************************************/ CREATE TABLE `config_info` ( `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT ‘id‘, `data_id` varchar(255) NOT NULL COMMENT ‘data_id‘, `group_id` varchar(255) DEFAULT NULL, `content` longtext NOT NULL COMMENT ‘content‘, `md5` varchar(32) DEFAULT NULL COMMENT ‘md5‘, `gmt_create` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘创建时间‘, `gmt_modified` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘修改时间‘, `src_user` text COMMENT ‘source user‘, `src_ip` varchar(20) DEFAULT NULL COMMENT ‘source ip‘, `app_name` varchar(128) DEFAULT NULL, `tenant_id` varchar(128) DEFAULT ‘‘ COMMENT ‘租户字段‘, `c_desc` varchar(256) DEFAULT NULL, `c_use` varchar(64) DEFAULT NULL, `effect` varchar(64) DEFAULT NULL, `type` varchar(64) DEFAULT NULL, `c_schema` text, PRIMARY KEY (`id`), UNIQUE KEY `uk_configinfo_datagrouptenant` (`data_id`,`group_id`,`tenant_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT=‘config_info‘; /******************************************/ /* 数据库全名 = nacos_config */ /* 表名称 = config_info_aggr */ /******************************************/ CREATE TABLE `config_info_aggr` ( `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT ‘id‘, `data_id` varchar(255) NOT NULL COMMENT ‘data_id‘, `group_id` varchar(255) NOT NULL COMMENT ‘group_id‘, `datum_id` varchar(255) NOT NULL COMMENT ‘datum_id‘, `content` longtext NOT NULL COMMENT ‘内容‘, `gmt_modified` datetime NOT NULL COMMENT ‘修改时间‘, `app_name` varchar(128) DEFAULT NULL, `tenant_id` varchar(128) DEFAULT ‘‘ COMMENT ‘租户字段‘, PRIMARY KEY (`id`), UNIQUE KEY `uk_configinfoaggr_datagrouptenantdatum` (`data_id`,`group_id`,`tenant_id`,`datum_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT=‘增加租户字段‘; /******************************************/ /* 数据库全名 = nacos_config */ /* 表名称 = config_info_beta */ /******************************************/ CREATE TABLE `config_info_beta` ( `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT ‘id‘, `data_id` varchar(255) NOT NULL COMMENT ‘data_id‘, `group_id` varchar(128) NOT NULL COMMENT ‘group_id‘, `app_name` varchar(128) DEFAULT NULL COMMENT ‘app_name‘, `content` longtext NOT NULL COMMENT ‘content‘, `beta_ips` varchar(1024) DEFAULT NULL COMMENT ‘betaIps‘, `md5` varchar(32) DEFAULT NULL COMMENT ‘md5‘, `gmt_create` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘创建时间‘, `gmt_modified` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘修改时间‘, `src_user` text COMMENT ‘source user‘, `src_ip` varchar(20) DEFAULT NULL COMMENT ‘source ip‘, `tenant_id` varchar(128) DEFAULT ‘‘ COMMENT ‘租户字段‘, PRIMARY KEY (`id`), UNIQUE KEY `uk_configinfobeta_datagrouptenant` (`data_id`,`group_id`,`tenant_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT=‘config_info_beta‘; /******************************************/ /* 数据库全名 = nacos_config */ /* 表名称 = config_info_tag */ /******************************************/ CREATE TABLE `config_info_tag` ( `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT ‘id‘, `data_id` varchar(255) NOT NULL COMMENT ‘data_id‘, `group_id` varchar(128) NOT NULL COMMENT ‘group_id‘, `tenant_id` varchar(128) DEFAULT ‘‘ COMMENT ‘tenant_id‘, `tag_id` varchar(128) NOT NULL COMMENT ‘tag_id‘, `app_name` varchar(128) DEFAULT NULL COMMENT ‘app_name‘, `content` longtext NOT NULL COMMENT ‘content‘, `md5` varchar(32) DEFAULT NULL COMMENT ‘md5‘, `gmt_create` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘创建时间‘, `gmt_modified` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘修改时间‘, `src_user` text COMMENT ‘source user‘, `src_ip` varchar(20) DEFAULT NULL COMMENT ‘source ip‘, PRIMARY KEY (`id`), UNIQUE KEY `uk_configinfotag_datagrouptenanttag` (`data_id`,`group_id`,`tenant_id`,`tag_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT=‘config_info_tag‘; /******************************************/ /* 数据库全名 = nacos_config */ /* 表名称 = config_tags_relation */ /******************************************/ CREATE TABLE `config_tags_relation` ( `id` bigint(20) NOT NULL COMMENT ‘id‘, `tag_name` varchar(128) NOT NULL COMMENT ‘tag_name‘, `tag_type` varchar(64) DEFAULT NULL COMMENT ‘tag_type‘, `data_id` varchar(255) NOT NULL COMMENT ‘data_id‘, `group_id` varchar(128) NOT NULL COMMENT ‘group_id‘, `tenant_id` varchar(128) DEFAULT ‘‘ COMMENT ‘tenant_id‘, `nid` bigint(20) NOT NULL AUTO_INCREMENT, PRIMARY KEY (`nid`), UNIQUE KEY `uk_configtagrelation_configidtag` (`id`,`tag_name`,`tag_type`), KEY `idx_tenant_id` (`tenant_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT=‘config_tag_relation‘; /******************************************/ /* 数据库全名 = nacos_config */ /* 表名称 = group_capacity */ /******************************************/ CREATE TABLE `group_capacity` ( `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT COMMENT ‘主键ID‘, `group_id` varchar(128) NOT NULL DEFAULT ‘‘ COMMENT ‘Group ID,空字符表示整个集群‘, `quota` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘配额,0表示使用默认值‘, `usage` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘使用量‘, `max_size` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘单个配置大小上限,单位为字节,0表示使用默认值‘, `max_aggr_count` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘聚合子配置最大个数,,0表示使用默认值‘, `max_aggr_size` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘单个聚合数据的子配置大小上限,单位为字节,0表示使用默认值‘, `max_history_count` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘最大变更历史数量‘, `gmt_create` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘创建时间‘, `gmt_modified` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘修改时间‘, PRIMARY KEY (`id`), UNIQUE KEY `uk_group_id` (`group_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT=‘集群、各Group容量信息表‘; /******************************************/ /* 数据库全名 = nacos_config */ /* 表名称 = his_config_info */ /******************************************/ CREATE TABLE `his_config_info` ( `id` bigint(64) unsigned NOT NULL, `nid` bigint(20) unsigned NOT NULL AUTO_INCREMENT, `data_id` varchar(255) NOT NULL, `group_id` varchar(128) NOT NULL, `app_name` varchar(128) DEFAULT NULL COMMENT ‘app_name‘, `content` longtext NOT NULL, `md5` varchar(32) DEFAULT NULL, `gmt_create` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP, `gmt_modified` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP, `src_user` text, `src_ip` varchar(20) DEFAULT NULL, `op_type` char(10) DEFAULT NULL, `tenant_id` varchar(128) DEFAULT ‘‘ COMMENT ‘租户字段‘, PRIMARY KEY (`nid`), KEY `idx_gmt_create` (`gmt_create`), KEY `idx_gmt_modified` (`gmt_modified`), KEY `idx_did` (`data_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT=‘多租户改造‘; /******************************************/ /* 数据库全名 = nacos_config */ /* 表名称 = tenant_capacity */ /******************************************/ CREATE TABLE `tenant_capacity` ( `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT COMMENT ‘主键ID‘, `tenant_id` varchar(128) NOT NULL DEFAULT ‘‘ COMMENT ‘Tenant ID‘, `quota` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘配额,0表示使用默认值‘, `usage` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘使用量‘, `max_size` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘单个配置大小上限,单位为字节,0表示使用默认值‘, `max_aggr_count` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘聚合子配置最大个数‘, `max_aggr_size` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘单个聚合数据的子配置大小上限,单位为字节,0表示使用默认值‘, `max_history_count` int(10) unsigned NOT NULL DEFAULT ‘0‘ COMMENT ‘最大变更历史数量‘, `gmt_create` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘创建时间‘, `gmt_modified` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘修改时间‘, PRIMARY KEY (`id`), UNIQUE KEY `uk_tenant_id` (`tenant_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT=‘租户容量信息表‘; CREATE TABLE `tenant_info` ( `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT ‘id‘, `kp` varchar(128) NOT NULL COMMENT ‘kp‘, `tenant_id` varchar(128) default ‘‘ COMMENT ‘tenant_id‘, `tenant_name` varchar(128) default ‘‘ COMMENT ‘tenant_name‘, `tenant_desc` varchar(256) DEFAULT NULL COMMENT ‘tenant_desc‘, `create_source` varchar(32) DEFAULT NULL COMMENT ‘create_source‘, `gmt_create` bigint(20) NOT NULL COMMENT ‘创建时间‘, `gmt_modified` bigint(20) NOT NULL COMMENT ‘修改时间‘, PRIMARY KEY (`id`), UNIQUE KEY `uk_tenant_info_kptenantid` (`kp`,`tenant_id`), KEY `idx_tenant_id` (`tenant_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT=‘tenant_info‘; CREATE TABLE `users` ( `username` varchar(50) NOT NULL PRIMARY KEY, `password` varchar(500) NOT NULL, `enabled` boolean NOT NULL ); CREATE TABLE `roles` ( `username` varchar(50) NOT NULL, `role` varchar(50) NOT NULL, UNIQUE INDEX `idx_user_role` (`username` ASC, `role` ASC) USING BTREE ); CREATE TABLE `permissions` ( `role` varchar(50) NOT NULL, `resource` varchar(512) NOT NULL, `action` varchar(8) NOT NULL, UNIQUE INDEX `uk_role_permission` (`role`,`resource`,`action`) USING BTREE ); INSERT INTO users (username, password, enabled) VALUES (‘nacos‘, ‘$2a$10$EuWPZHzz32dJN7jexM34MOeYirDdFAZm2kuWj7VEOJhhZkDrxfvUu‘, TRUE); INSERT INTO roles (username, role) VALUES (‘nacos‘, ‘ROLE_ADMIN‘);
在此目录中运行命令docker-compose up ,Nacos服务启动。
创建应用目录并将生成的provider与consumer的jar包拷贝过来:
根据dcokerfile 生成各自服务镜像,Dockerfile-provider 文件:
FROM openjdk:8
COPY . /usr/src/myapp
WORKDIR /usr/src/myapp
CMD ["java", "-jar","provider-1.0.jar"]
Dockerfile-consumer文件:
FROM openjdk:8
COPY . /usr/src/myapp
WORKDIR /usr/src/myapp
CMD ["java", "-jar","consumer-1.0.jar"]
创建镜像: docker build . -t provider -f .\Dockerfile-provider ,docker build . -t provider -f .\Dockerfile-consumer
此目录Docker-compose.yml:
version: "3.1"
services:
dubbo-provider:
image: provider
container_name: provider
hostname: provider
restart: "no"
networks:
- localnet
external_links:
- nacos-standalone-mysql:nacosserver
dubbo-custom:
image: consumer
container_name: consumer
hostname: consumer
restart: "no"
ports:
- 8080:8080
networks:
- localnet
external_links:
- nacos-standalone-mysql:nacoserver
depends_on:
- dubbo-provider
networks:
localnet:
external: true
在此目录中运行 docker-compose up 启动应用服务
服务正常情况如图:
Nacos网页查看已注册服务
运行测试 http://nacosserver:8080/?name=abc
配置中心未配置时输出:
在配置中心进行配置:
再次刷新网址此时输出 :
至此整个过程已跑通,以此做为笔记,为以后快速创建项目提供参考
Spring Cloud Alibaba Dubbo 实践 + Docker编排
原文:https://www.cnblogs.com/coder-fang/p/13091747.html