一、什么是Spring Boot Admin ?

Spring Boot Admin是一个开源社区项目,用于管理和监控SpringBoot应用程序。 应用程序作为Spring Boot Admin Client向为Spring Boot Admin Server注册(通过HTTP)或使用SpringCloud注册中心(例如Eureka,Consul)发现。 UI是的Vue.js应用程序,展示Spring Boot Admin Client的Actuator端点上的一些监控。服务端采用Spring WebFlux + Netty的方式。Spring Boot Admin为注册的应用程序提供以下功能:

  • 显示健康状况
  • 显示详细信息,例如
  • JVM和内存指标
  • micrometer.io指标
  • 数据源指标
  • 缓存指标
  • 显示构建信息编号
  • 关注并下载日志文件
  • 查看jvm system-和environment-properties
  • 查看Spring Boot配置属性
  • 支持Spring Cloud的postable / env-和/ refresh-endpoint
  • 轻松的日志级管理
  • 与JMX-beans交互
  • 查看线程转储
  • 查看http-traces
  • 查看auditevents
  • 查看http-endpoints
  • 查看计划任务
  • 查看和删除活动会话(使用spring-session)
  • 查看Flyway / Liquibase数据库迁移
  • 下载heapdump
  • 状态变更通知(通过电子邮件,Slack,Hipchat,......)
  • 状态更改的事件日志(非持久性)

二、入门

1. 创建 Spring Boot Admin Server

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">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.gf</groupId>
<artifactId>admin-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>admin-server</name>
<description>Demo project for Spring Boot</description> <properties>
<java.version>1.8</java.version>
<spring-boot-admin.version>2.1.0</spring-boot-admin.version>
</properties> <dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-server</artifactId>
</dependency> <dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies> <dependencyManagement>
<dependencies>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-dependencies</artifactId>
<version>${spring-boot-admin.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>

application.yml

spring:
application:
name: admin-server
server:
port: 8769

启动类 AdminServerApplication

启动类加上@EnableAdminServer注解,开启AdminServer的功能:

@SpringBootApplication
@EnableAdminServer
public class AdminServerApplication { public static void main(String[] args) {
SpringApplication.run( AdminServerApplication.class, args );
} }

2. 创建 Spring Boot Admin Client

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">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.gf</groupId>
<artifactId>admin-client</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>admin-client</name>
<description>Demo project for Spring Boot</description> <properties>
<java.version>1.8</java.version>
<spring-boot-admin.version>2.1.0</spring-boot-admin.version>
</properties> <dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-client</artifactId>
</dependency> <dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies> <dependencyManagement>
<dependencies>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-dependencies</artifactId>
<version>${spring-boot-admin.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>

application.yml

  • spring.boot.admin.client.url:要注册的Spring Boot Admin Server的URL。
  • management.endpoints.web.exposure.include:与Spring Boot 2一样,默认情况下,大多数actuator的端口都不会通过http公开,* 代表公开所有这些端点。对于生产环境,应该仔细选择要公开的端点。
spring:
application:
name: admin-client
boot:
admin:
client:
url: http://localhost:8769
server:
port: 8768 management:
endpoints:
web:
exposure:
include: '*'
endpoint:
health:
show-details: ALWAYS

启动类 AdminClientApplication

@SpringBootApplication
public class AdminClientApplication { public static void main(String[] args) {
SpringApplication.run( AdminClientApplication.class, args );
} }

启动两个工程,在浏览器上输入localhost:8769 ,浏览器显示的界面如下:

查看wallboard:

点击wallboard,可以查看admin-client具体的信息,比如内存状态信息:

查看spring bean的情况:

查看应用程序运行状况,信息和详细:

还有很多监控信息,多点一点就知道。

三、集成 Eureka

1. 创建 sc-eureka-server

这是一个 eureka-server 注册中心。

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">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.gf</groupId>
<artifactId>sc-admin-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>sc-admin-server</name>
<description>Demo project for Spring Boot</description> <properties>
<java.version>1.8</java.version>
<spring-boot-admin.version>2.1.0</spring-boot-admin.version>
<spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
</properties> <dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-server</artifactId>
<version>2.1.0</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency> <dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-mail</artifactId>
</dependency>
<dependency>
<groupId>org.jolokia</groupId>
<artifactId>jolokia-core</artifactId>
</dependency>
</dependencies> <dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-dependencies</artifactId>
<version>${spring-boot-admin.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>

application.yml

spring:
application:
name: sc-eureka-server
server:
port: 8761
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka
register-with-eureka: false
fetch-registry: false
management:
endpoints:
web:
exposure:
include: "*"
endpoint:
health:
show-details: ALWAYS

启动类 ScEurekaServerApplication

@SpringBootApplication
@EnableEurekaServer
public class ScEurekaServerApplication { public static void main(String[] args) {
SpringApplication.run( ScEurekaServerApplication.class, args );
} }

2. 创建 sc-admin-server

这是一个 Spring Boot Admin Server端。

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">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.gf</groupId>
<artifactId>sc-admin-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>sc-admin-server</name>
<description>Demo project for Spring Boot</description> <properties>
<java.version>1.8</java.version>
<spring-boot-admin.version>2.1.0</spring-boot-admin.version>
<spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
</properties> <dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-server</artifactId>
<version>2.1.0</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency> <dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-mail</artifactId>
</dependency>
<dependency>
<groupId>org.jolokia</groupId>
<artifactId>jolokia-core</artifactId>
</dependency>
</dependencies> <dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-dependencies</artifactId>
<version>${spring-boot-admin.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>

application.yml

spring:
application:
name: admin-server
server:
port: 8769
eureka:
client:
registryFetchIntervalSeconds: 5
service-url:
defaultZone: ${EUREKA_SERVICE_URL:http://localhost:8761}/eureka/
instance:
leaseRenewalIntervalInSeconds: 10
health-check-url-path: /actuator/health management:
endpoints:
web:
exposure:
include: "*"
endpoint:
health:
show-details: ALWAYS

启动类 ScAdminServerApplication

@SpringBootApplication
@EnableAdminServer
@EnableDiscoveryClient
public class ScAdminServerApplication { public static void main(String[] args) {
SpringApplication.run( ScAdminServerApplication.class, args );
} }

3. 创建 sc-admin-client

这是一个 Spring Boot Admin client 端。

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">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.gf</groupId>
<artifactId>sc-admin-client</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>sc-admin-client</name>
<description>Demo project for Spring Boot</description> <properties>
<java.version>1.8</java.version>
<spring-boot-admin.version>2.1.0</spring-boot-admin.version>
<spring-cloud.version>Finchley.SR2</spring-cloud.version>
</properties> <dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</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-webflux</artifactId>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-starter-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency> <dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies> <dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>de.codecentric</groupId>
<artifactId>spring-boot-admin-dependencies</artifactId>
<version>${spring-boot-admin.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>

application.yml

spring:
application:
name: sc-admin-client
eureka:
instance:
leaseRenewalIntervalInSeconds: 10
health-check-url-path: /actuator/health client:
registryFetchIntervalSeconds: 5
service-url:
defaultZone: ${EUREKA_SERVICE_URL:http://localhost:8761}/eureka/
management:
endpoints:
web:
exposure:
include: "*"
endpoint:
health:
show-details: ALWAYS
server:
port: 8762

启动类 ScAdminClientApplication

@SpringBootApplication
@EnableDiscoveryClient
public class ScAdminClientApplication { public static void main(String[] args) {
SpringApplication.run( ScAdminClientApplication.class, args );
} }

启动三个工程,访问localhost:8769,出现如下界面:

admin 会自己拉取 Eureka 上注册的 app 信息,主动去注册。这也是唯一区别之前入门中手动注册的地方,就是 client 端不需要 admin-client 的依赖,也不需要配置 admin 地址了,一切全部由 admin-server 自己实现。这样的设计对环境变化很友好,不用改了admin-server后去改所有app 的配置了。

四、集成 Spring Security

Web应用程序中的身份验证和授权有多种方法,因此Spring Boot Admin不提供默认方法。默认情况下,spring-boot-admin-server-ui提供登录页面和注销按钮。我们结合 Spring Security 实现需要用户名和密码登录的安全认证。

sc-admin-server工程的pom文件需要增加以下的依赖:

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>

在 sc-admin-server工的配置文件 application.yml 中配置 spring security 的用户名和密码,这时需要在服务注册时带上 metadata-map 的信息,如下:

spring:
security:
user:
name: "admin"
password: "admin" eureka:
instance:
metadata-map:
user.name: ${spring.security.user.name}
user.password: ${spring.security.user.password}

@EnableWebSecurity注解以及WebSecurityConfigurerAdapter一起配合提供基于web的security。继承了WebSecurityConfigurerAdapter之后,再加上几行代码,我们就能实现要求用户在进入应用的任何URL之前都进行验证的功能,写一个配置类SecuritySecureConfig继承WebSecurityConfigurerAdapter,配置如下:

@Configuration
public class SecuritySecureConfig extends WebSecurityConfigurerAdapter { private final String adminContextPath; public SecuritySecureConfig(AdminServerProperties adminServerProperties) {
this.adminContextPath = adminServerProperties.getContextPath();
} @Override
protected void configure(HttpSecurity http) throws Exception {
// @formatter:off
SavedRequestAwareAuthenticationSuccessHandler successHandler = new SavedRequestAwareAuthenticationSuccessHandler();
successHandler.setTargetUrlParameter("redirectTo");
successHandler.setDefaultTargetUrl(adminContextPath + "/"); http.authorizeRequests()
//授予对所有静态资产和登录页面的公共访问权限。
.antMatchers(adminContextPath + "/assets/**").permitAll()
.antMatchers(adminContextPath + "/login").permitAll()
//必须对每个其他请求进行身份验证
.anyRequest().authenticated()
.and()
//配置登录和注销
.formLogin().loginPage(adminContextPath + "/login").successHandler(successHandler).and()
.logout().logoutUrl(adminContextPath + "/logout").and()
//启用HTTP-Basic支持。这是Spring Boot Admin Client注册所必需的
.httpBasic().and();
// @formatter:on
}
}

重新访问 http://localhost:8769/ 会出现登录界面,密码是 配置文件中配置好的,账号 admin 密码 admin,界面如下:

五、通知

1. 邮件通知

在 Spring Boot Admin 中 当注册的应用程序状态更改为DOWN、UNKNOWN、OFFLINE 都可以指定触发通知,下面讲解配置邮件通知。

在sc-admin-server工程pom文件,加上mail的依赖,如下:

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-mail</artifactId>
</dependency>

在配置文件application.yml文件中,配置收发邮件的配置:

spring:
mail:
host: smtp.163.com
username: xxxx@163.com
password: xxxx
properties:
mail:
smtp:
auth: true
starttls:
enable: true
required: true
boot:
admin:
notify:
mail:
from: xxxx@163.com
to: xxxx@qq.com

配置后,重启sc-admin-server工程,之后若出现注册的客户端的状态从 UP 变为 OFFLINE 或其他状态,服务端就会自动将电子邮件发送到上面配置的收件地址。

注意 : 配置了邮件通知后,会出现 反复通知 service offline / up。这个问题的原因在于 查询应用程序的状态和信息超时,下面给出两种解决方案:

#方法一:增加超时时间(单位:ms)

spring.boot.admin.monitor.read-timeout=20000

#方法二:关闭闭未使用或不重要的检查点

management.health.db.enabled=false
management.health.mail.enabled=false
management.health.redis.enabled=false
management.health.mongo.enabled=false

2. 自定义通知

可以通过添加实现Notifier接口的Spring Beans来添加您自己的通知程序,最好通过扩展 AbstractEventNotifier或AbstractStatusChangeNotifier。在sc-admin-server工程中编写一个自定义的通知器:

@Component
public class CustomNotifier extends AbstractStatusChangeNotifier {
private static final Logger LOGGER = LoggerFactory.getLogger( LoggingNotifier.class); public CustomNotifier(InstanceRepository repository) {
super(repository);
} @Override
protected Mono<Void> doNotify(InstanceEvent event, Instance instance) {
return Mono.fromRunnable(() -> {
if (event instanceof InstanceStatusChangedEvent) {
LOGGER.info("Instance {} ({}) is {}", instance.getRegistration().getName(), event.getInstance(),
((InstanceStatusChangedEvent) event).getStatusInfo().getStatus()); String status = ((InstanceStatusChangedEvent) event).getStatusInfo().getStatus(); switch (status) {
// 健康检查没通过
case "DOWN":
System.out.println("发送 健康检查没通过 的通知!");
break;
// 服务离线
case "OFFLINE":
System.out.println("发送 服务离线 的通知!");
break;
//服务上线
case "UP":
System.out.println("发送 服务上线 的通知!");
break;
// 服务未知异常
case "UNKNOWN":
System.out.println("发送 服务未知异常 的通知!");
break;
default:
break;
} } else {
LOGGER.info("Instance {} ({}) {}", instance.getRegistration().getName(), event.getInstance(),
event.getType());
}
});
}
}

源码下载:https://github.com/gf-huanchupk/SpringBootLearning/tree/master/springboot-admin

欢迎扫码或微信搜索公众号《程序员果果》关注我,关注有惊喜~

Spring Boot admin 2.0 详解的更多相关文章

  1. Spring Boot(八):RabbitMQ详解

    Spring Boot(八):RabbitMQ详解 RabbitMQ 即一个消息队列,主要是用来实现应用程序的异步和解耦,同时也能起到消息缓冲,消息分发的作用. 消息中间件在互联网公司的使用中越来越多 ...

  2. Spring Boot Actuator监控使用详解

    在企业级应用中,学习了如何进行SpringBoot应用的功能开发,以及如何写单元测试.集成测试等还是不够的.在实际的软件开发中还需要:应用程序的监控和管理.SpringBoot的Actuator模块实 ...

  3. Spring Boot 之使用 Json 详解

    Spring Boot 之使用 Json 详解 简介 Spring Boot 支持的 Json 库 Spring Web 中的序列化.反序列化 指定类的 Json 序列化.反序列化 @JsonTest ...

  4. Spring Boot启动命令参数详解及源码分析

    使用过Spring Boot,我们都知道通过java -jar可以快速启动Spring Boot项目.同时,也可以通过在执行jar -jar时传递参数来进行配置.本文带大家系统的了解一下Spring ...

  5. Spring Boot的启动器Starter详解

    Spring Boot的启动器Starter详解 作者:chszs,未经博主允许不得转载.经许可的转载需注明作者和博客主页:http://blog.csdn.net/chszs Spring Boot ...

  6. Spring boot注解(annotation)含义详解

    Spring boot注解(annotation)含义详解 @Service用于标注业务层组件@Controller用于标注控制层组件(如struts中的action)@Repository用于标注数 ...

  7. Spring Boot中@ConditionalOnProperty使用详解

    在Spring Boot的自动配置中经常看到@ConditionalOnProperty注解的使用,本篇文章带大家来了解一下该注解的功能. Spring Boot中的使用 在Spring Boot的源 ...

  8. spring boot application.properties 属性详解

    2019年3月21日17:09:59 英文原版: https://docs.spring.io/spring-boot/docs/current/reference/html/common-appli ...

  9. Spring Boot:Thymeleaf 使用详解

    Thymeleaf 介绍 简单说,Thymeleaf 是一个跟 Velocity.FreeMarker 类似的模板引擎,它可以完全替代 JSP .相较与其他的模板引擎,它有如下三个极吸引人的特点: 1 ...

随机推荐

  1. 手动安装composer详细教学

    1.下载compser.phar 地址 https://getcomposer.org/download/ 2.新建composer.bat 文件,写入“@php "%~dp0compose ...

  2. C语言复习3_条件结构

    if条件结构 if else 结构一般处理区间情况 #include <stdio.h> #include <stdlib.h> int main() { //打印剧情 dou ...

  3. Meltdown Attack

    1. 引言 2018年1月3日,Google Project Zero(GPZ)团队安全研究员Jann Horn在其团队博客中爆出CPU芯片的两组漏洞,分别是Meltdown与Spectre. Mel ...

  4. freemarker导出带图片的word文档

    最近做一个关于文档导出功能, 顺便学习了下freemarker,做了个关于导出带图片的word文档,模板并没有写全,只是验证代码的正确性 这只是做一个小功能,故只做了后台代码关于导出的代码,并未与前台 ...

  5. android studio 撤销和恢复

    我的Android studio版本是2.2版本 1.Ctrl+z是撤销快捷键 2.如果Ctrl+z 掉的内容,又反悔了,快捷键为:Ctrl + Shift + z.

  6. ReactJs和React Native的联系和差异

    1,React Js的目的 是为了使前端的V层更具组件化,能更好的复用,它能够使用简单的html标签创建更多的自定义组件标签,内部绑定事件,同时可以让你从操作dom中解脱出来,只需要操作数据就会改变相 ...

  7. [Swift]LeetCode250.计数相同值子树的个数 $ Count Univalue Subtrees

    Given a binary tree, count the number of uni-value subtrees. A Uni-value subtree means all nodes of ...

  8. spring统一错误响应设置

    在类入口增加 @RestControllerAdvice注解.可以用于定义@ExceptionHandler.@InitBinder.@ModelAttribute,并应用到所有@RequestMap ...

  9. 【Scala篇】--Scala初始与基础

    一.前述 Scala是基于JVM的另一个语言. Scala官网6个特征. 1).Java和scala可以混编 2).类型推测(自动推测类型) 3).并发和分布式(Actor) 4).特质,特征(类似j ...

  10. Python内置函数(45)——object

    英文文档: class objectReturn a new featureless object. object is a base for all classes. It has the meth ...