SpringBoot入门-2(两种热部署方式)

在编写代码的时候，你会发现我们只是简单把打印信息改变了，就需要重新部署，如果是这样的编码方式，那么我们估计一天下来就真的是打几个Hello World就下班了。那么如何解决热部署的问题呢？那就是springloaded

　1、在1的基础上，pom文件添加一个plugin节点

<plugin>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-maven-plugin</artifactId>
  <dependencies>
   <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>springloaded</artifactId>
    <version>1.2.6.RELEASE</version>
   </dependency>
  </dependencies>
 </plugin>

　　2、这次启动不能直接运行 main 方法了，需要点击项目右键>>Run As >>Maven build...>>输入spring-boot:run启动，之后修改java文件测试

package com.test;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @RestController 相当于@Controller和@RequestBody
 *
 */
@RestController
@EnableAutoConfiguration
public class HelloController {

    @RequestMapping("/hello")
    public String hello(){
        System.out.println("22");
        return "Hello Word SpringBootabbb";
    }

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

　　完成热部署，但是这个关闭时，重新启动会发现端口被占用，端口未被关闭，还在运行着，需要在任务管理器中进行关闭java.exe

java.net.BindException: Address already in use: bind
    at sun.nio.ch.Net.bind0(Native Method) ~[na:1.7.0_45]
    at sun.nio.ch.Net.bind(Net.java:444) ~[na:1.7.0_45]
    at sun.nio.ch.Net.bind(Net.java:436) ~[na:1.7.0_45]
    at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:214) ~[na:1.7.0_45]
    at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74) ~[na:1.7.0_45]
    at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:340) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint.java:773) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.apache.coyote.AbstractProtocol.start(AbstractProtocol.java:473) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.apache.catalina.connector.Connector.startInternal(Connector.java:986) [tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147) [tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.apache.catalina.core.StandardService.addConnector(StandardService.java:239) [tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.addPreviouslyRemovedConnectors(TomcatEmbeddedServletContainer.java:194) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.start(TomcatEmbeddedServletContainer.java:151) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.startEmbeddedServletContainer(EmbeddedWebApplicationContext.java:293) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.finishRefresh(EmbeddedWebApplicationContext.java:141) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) [spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at com.test.HelloController.main(HelloController.java:24) [classes/:na]

2017-08-12 15:55:39.128 ERROR 1136 --- [           main] o.apache.catalina.core.StandardService   : Failed to start connector [Connector[HTTP/1.1-8080]]

org.apache.catalina.LifecycleException: Failed to start component [Connector[HTTP/1.1-8080]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.apache.catalina.core.StandardService.addConnector(StandardService.java:239) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.addPreviouslyRemovedConnectors(TomcatEmbeddedServletContainer.java:194) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.start(TomcatEmbeddedServletContainer.java:151) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.startEmbeddedServletContainer(EmbeddedWebApplicationContext.java:293) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.finishRefresh(EmbeddedWebApplicationContext.java:141) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) [spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at com.test.HelloController.main(HelloController.java:24) [classes/:na]
Caused by: org.apache.catalina.LifecycleException: service.getName(): "Tomcat";  Protocol handler start failed
    at org.apache.catalina.connector.Connector.startInternal(Connector.java:993) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
    ... 13 common frames omitted
Caused by: java.net.BindException: Address already in use: bind
    at sun.nio.ch.Net.bind0(Native Method) ~[na:1.7.0_45]
    at sun.nio.ch.Net.bind(Net.java:444) ~[na:1.7.0_45]
    at sun.nio.ch.Net.bind(Net.java:436) ~[na:1.7.0_45]
    at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:214) ~[na:1.7.0_45]
    at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74) ~[na:1.7.0_45]
    at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:340) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint.java:773) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.apache.coyote.AbstractProtocol.start(AbstractProtocol.java:473) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
    at org.apache.catalina.connector.Connector.startInternal(Connector.java:986) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
    ... 14 common frames omitted

2017-08-12 15:55:39.165  INFO 1136 --- [           main] o.apache.catalina.core.StandardService   : Stopping service Tomcat
2017-08-12 15:55:39.193 ERROR 1136 --- [           main] o.s.boot.SpringApplication               : Application startup failed

org.springframework.boot.context.embedded.EmbeddedServletContainerException: Unable to start embedded Tomcat servlet container
    at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.start(TomcatEmbeddedServletContainer.java:165) ~[spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.startEmbeddedServletContainer(EmbeddedWebApplicationContext.java:293) ~[spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.finishRefresh(EmbeddedWebApplicationContext.java:141) ~[spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) ~[spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    at com.test.HelloController.main(HelloController.java:24) [classes/:na]
Caused by: java.lang.IllegalStateException: Tomcat connector in failed state
    at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.start(TomcatEmbeddedServletContainer.java:159) ~[spring-boot-1.3.4.RELEASE.jar:1.3.4.RELEASE]
    ... 10 common frames omitted

或者采用另一个运行方式，可以解决此问题。

使用run as – java application，

那么还需要做一些处理。

把spring-loader-1.2.4.RELEASE.jar下载下来，放到项目的lib目录中，

然后把IDEA的run参数里VM参数设置为：
-javaagent:.\lib\springloaded-1.2.4.RELEASE.jar -noverify

然后启动就可以了，这样在run as的时候，也能进行热部署

通过使用springloaded进行热部署，但是些代码修改了，并不会进行热部署

　　第二种热部署方式之devtools

spring-boot-devtools 是一个为开发者服务的一个模块，其中最重要的功能就是自动应用代码更改到最新的App上面去。

原理是在发现代码有更改之后，重新启动应用，但是速度比手动停止后再启动还要更快，更快指的不是节省出来的手工操作的时间。

其深层原理是使用了两个ClassLoader，一个Classloader加载那些不会改变的类（第三方Jar包），另一个ClassLoader加载会更改的类，

称为 restart ClassLoader
,这样在有代码更改的时候，原来的restart ClassLoader 被丢弃，重新创建一个restart ClassLoader，由于需要加载的类相比较少，

所以实现了较快的重启时间（5秒以内）。

1、maven的pom文件配置

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

 <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <fork>true</fork><!-- 如果没有该项配置，肯呢个devtools不会起作用，即应用不会restart -->
                </configuration>
            </plugin>

然后就完成了

devtools会监听classpath下的文件变动，并且会立即重启应用（发生在保存时机），注意：因为其采用的虚拟机机制，该项重启是很快的。

---- Run Application --- Java Application即可测试

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