1.Tomcat9安裝配置
- step1.配置Java
JAVA_HOME
PATH=%JAVA_HOME%\bin;
CLASSPATH=.;%JAVA_HOME%\lib\dt.jar;%JAVA_HOME%\lib\tools.jar; - step2.配置tomcat
TOMCAT_HOME=D:\apache-tomcat-9.0.12
CATALINA_HOME=D:\apache-tomcat-9.0.12
PATH=%CATALINA_HOME%\bin
CLASSPATH=%CATALINA_HOME%\lib\servlet-api.jar - step3.安裝
cmd輸入service install Tomcat9 - step4.測(cè)試
控制面板—系統(tǒng)和安全—管理工具—服務(wù)猜丹，找到Apache Tomcat Tomcat9服務(wù)項(xiàng)沪伙，右擊該項(xiàng)僵闯，點(diǎn)“啟動(dòng)”缅刽，啟動(dòng)該服務(wù)。
地址欄輸入http://localhost:8080或 http://127.0.0.1:8080
如果出現(xiàn)tomcat示例主頁(yè)梗搅，則表示服務(wù)器安裝成功禾唁。
2.新建動(dòng)態(tài)web項(xiàng)目
-
step1.新建web項(xiàng)目
3.原生的servlet3.0測(cè)試
以前來(lái)寫(xiě)web的三大組件：以前寫(xiě)servlet filter listener都需要在web.xml進(jìn)行注冊(cè)效览，包括springmvc的前端控制器DispactherServlet也需要在web.xml注冊(cè)，現(xiàn)在可以通過(guò)注解的方式快速搭建我們的web應(yīng)用荡短。
3.1 簡(jiǎn)單的測(cè)試
- 新增請(qǐng)求地址丐枉，請(qǐng)求地址為order
index.jsp
<html>
<head>
<title>$Title$</title>
</head>
<body>
<a href="order">order</a>
</body>
</html>
- 建立一個(gè)原生的servlet來(lái)處理 order的請(qǐng)求
JamesServlet.java
@WebServlet("/order")
public class JamesServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
resp.getWriter().write("order success...");
}
}
-
啟動(dòng)tomcat后測(cè)試
3.2 ServletContainerInitializer初始化web容器
Shared libraries（共享庫(kù)） and runtimes pluggability（運(yùn)行時(shí)插件）的原理，在后面的框架整合里掘托，用得比較多瘦锹。
在web容器啟動(dòng)時(shí)為提供給第三方組件機(jī)會(huì)做一些初始化的工作，例如注冊(cè)servlet或者filters等闪盔，servlet規(guī)范(JSR356)中通過(guò)ServletContainerInitializer實(shí)現(xiàn)此功能弯院。
每個(gè)框架要使用ServletContainerInitializer就必須在對(duì)應(yīng)的jar包的META-INF/services 目錄創(chuàng)建一個(gè)名為javax.servlet.ServletContainerInitializer的文件，文件內(nèi)容指定具體的ServletContainerInitializer實(shí)現(xiàn)類(lèi)泪掀，那么听绳，當(dāng)web容器啟動(dòng)時(shí)就會(huì)運(yùn)行這個(gè)初始化器做一些組件內(nèi)的初始化工作。
- 在src下創(chuàng)建META-INF/services目錄
創(chuàng)建javax.servlet.ServletContainerInitializer文件异赫。
com.wangzhen.servlet.JamesServletContainerInitializer
- 新建JamesServletContainerInitializer實(shí)現(xiàn)ServletContainerInitializer接口
JamesServletContainerInitializer.java
@HandlesTypes(value={JamesService.class})
public class JamesServletContainerInitializer implements ServletContainerInitializer {
/**
* tomcat啟動(dòng)時(shí)加載應(yīng)用的時(shí)候椅挣，會(huì)運(yùn)行onStartup方法；
*
* Set<Class<?>> arg0：感興趣的類(lèi)型的所有子類(lèi)型(對(duì)實(shí)現(xiàn)了JamesService接口相關(guān)的)塔拳；
* ServletContext arg1:代表當(dāng)前Web應(yīng)用的ServletContext鼠证；一個(gè)Web應(yīng)用一個(gè)ServletContext；
*
* 1）蝙斜、使用ServletContext注冊(cè)Web組件（Servlet、Filter澎胡、Listener）
* 2）孕荠、使用編碼的方式，在項(xiàng)目啟動(dòng)的時(shí)候給ServletContext里面添加組件攻谁；
* 必須在項(xiàng)目啟動(dòng)的時(shí)候來(lái)添加；
* 1）戚宦、ServletContainerInitializer得到的ServletContext个曙；
* 2）艳汽、ServletContextListener得到的ServletContext猴贰；
*/
@Override
public void onStartup(Set<Class<?>> arg0, ServletContext arg1) throws ServletException {
System.out.println("感興趣的類(lèi)型：");
for (Class<?> claz : arg0) {
System.out.println(claz);//當(dāng)傳進(jìn)來(lái)后，可以根據(jù)自己需要利用反射來(lái)創(chuàng)建對(duì)象等操作
}
}
}
并新建JamesService接口的所有子類(lèi)型
JamesServiceOther
JamesServiceImpl
AbstractJamesService測(cè)試結(jié)果
Connected to server
[2018-09-14 06:57:00,891] Artifact wangzhen-servlet3:war exploded: Artifact is being deployed, please wait...
感興趣的類(lèi)型：
interface com.wangzhen.service.JamesServiceOther
class com.wangzhen.service.AbstractJamesService
class com.wangzhen.service.JamesServiceImpl
- 總結(jié)
實(shí)質(zhì)是基于運(yùn)行時(shí)插件的機(jī)制河狐，啟動(dòng)并運(yùn)行這個(gè)ServletContainerInitializer米绕，在整合springmvc的時(shí)候會(huì)用到
3.3 使用ServletContext注冊(cè)web組件
其實(shí)就是Servlet,Filter,Listener三大組件瑟捣。
對(duì)于我們自己寫(xiě)的JamesServlet，我們可以使用@WebServlet注解來(lái)加入JamesServlet組件栅干，
但若是我們要導(dǎo)入第三方阿里的連接池或filter迈套，以前的web.xml方式就可通過(guò)配置加載就可以了，但現(xiàn)在我們使用ServletContext注入進(jìn)來(lái)碱鳞。
@Override
public void onStartup(Set<Class<?>> arg0, ServletContext arg1) throws ServletException {
System.out.println("感興趣的類(lèi)型：");
for (Class<?> claz : arg0) {
System.out.println(claz);//當(dāng)傳進(jìn)來(lái)后桑李，可以根據(jù)自己需要利用反射來(lái)創(chuàng)建對(duì)象等操作
}
//注冊(cè)servlet組件
javax.servlet.ServletRegistration.Dynamic servlet = arg1.addServlet("orderServlet", new OrderServlet());
//配置servlet的映射信息（路徑請(qǐng)求）
servlet.addMapping("/orderTest");
//注冊(cè)監(jiān)聽(tīng)器Listener
arg1.addListener(OrderListener.class);
//注冊(cè)Filter
javax.servlet.FilterRegistration.Dynamic filter = arg1.addFilter("orderFilter", OrderFilter.class);
//添加Filter的映射信息，可以指定專(zhuān)門(mén)來(lái)攔截哪個(gè)servlet
filter.addMappingForUrlPatterns(EnumSet.of(DispatcherType.REQUEST), true, "/*");
}
}
- 新建三個(gè)組件
public class OrderFilter implements Filter {
@Override
public void destroy() {
// TODO Auto-generated method stub
}
@Override
public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
throws IOException, ServletException {
// 過(guò)濾請(qǐng)求
System.out.println("UserFilter...doFilter...");
//放行
arg2.doFilter(arg0, arg1);
}
@Override
public void init(FilterConfig arg0) throws ServletException {
// TODO Auto-generated method stub
}
}
public class OrderListener implements ServletContextListener {
//監(jiān)聽(tīng)ServletContext銷(xiāo)毀
@Override
public void contextDestroyed(ServletContextEvent arg0) {
// TODO Auto-generated method stub
System.out.println("UserListener...contextDestroyed...");
}
//監(jiān)聽(tīng)ServletContext啟動(dòng)初始化
@Override
public void contextInitialized(ServletContextEvent arg0) {
// TODO Auto-generated method stub
ServletContext servletContext = arg0.getServletContext();
System.out.println("UserListener...contextInitialized...");
}
}
public class OrderServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
resp.getWriter().write("jamesServlet...");
}
}
-
測(cè)試結(jié)果
UserListener...contextInitialized...
[2018-09-14 07:38:34,459] Artifact wangzhen-servlet3:war exploded: Artifact is deployed successfully
[2018-09-14 07:38:34,459] Artifact wangzhen-servlet3:war exploded: Deploy took 567 milliseconds
UserFilter...doFilter...
UserFilter...doFilter...
UserFilter...doFilter...
UserFilter...doFilter...
14-Sep-2018 19:38:43.547 信息 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [D:\apache-tomcat-9.0.12\webapps\manager]
14-Sep-2018 19:38:43.587 信息 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [D:\apache-tomcat-9.0.12\webapps\manager] has finished in [40] ms
UserFilter...doFilter...
注意：在運(yùn)行的過(guò)程中劫笙，是不可以注冊(cè)組件芙扎， 和IOC道理一樣，出于安全考慮填大。
4.SpringMVC
4.1 簡(jiǎn)單的項(xiàng)目
- 新建maven工程戒洼，配置pom.xml。
<groupId>com.wangzhen</groupId>
<artifactId>springmvc-learn</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.0.6.RELEASE</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>3.0-alpha-1</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.4</version>
<configuration>
<failOnMissingWebXml>false</failOnMissingWebXml>
</configuration>
</plugin>
</plugins>
</build>
注意：tomcat也有servlet允华，maven打jar包的時(shí)候不要把它打進(jìn)去圈浇，不然會(huì)重復(fù)。
-
查看maven的一個(gè)spring-web.jar包
內(nèi)容是：
org.springframework.web.SpringServletContainerInitializer
- JamesWebAppInitializer
public class JamesWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
//獲取根容器的配置類(lèi)靴寂；（Spring的配置文件） 父容器磷蜀；
@Override
protected Class<?>[] getRootConfigClasses() {
//指定配置類(lèi)（配置文件）位置
return new Class<?>[]{JamesRootConfig.class} ;
}
//獲取web容器的配置類(lèi)（SpringMVC配置文件） 子容器；
@Override
protected Class<?>[] getServletConfigClasses() {
return new Class<?>[]{JamesAppConfig.class} ;
}
//獲取DispatcherServlet的映射信息
// /：攔截所有請(qǐng)求（包括靜態(tài)資源（xx.js,xx.png））百炬，但是不包括*.jsp褐隆；
// /*：攔截所有請(qǐng)求；連*.jsp頁(yè)面都攔截剖踊；jsp頁(yè)面是tomcat的jsp引擎解析的庶弃；
@Override
protected String[] getServletMappings() {
// TODO Auto-generated method stub
return new String[]{"/"};
}
}
- 新建兩個(gè)配置類(lèi)JamesRootConfig和JamesAppConfig，形成父子容器的效果
//Spring的容器不掃描controller;父容器
@ComponentScan(value="com.wangzhen",excludeFilters={
@ComponentScan.Filter(type=FilterType.ANNOTATION,classes={Controller.class})
})
public class JamesRootConfig {
}
//SpringMVC只掃描Controller德澈；子容器
//useDefaultFilters=false 禁用默認(rèn)的過(guò)濾規(guī)則歇攻；
@ComponentScan(value="com.wangzhen",includeFilters={
@ComponentScan.Filter(type=FilterType.ANNOTATION,classes={Controller.class})
},useDefaultFilters=false)
public class JamesAppConfig {
}
- 測(cè)試類(lèi)
Controller
public class OrderController {
@Autowired
OrderService orderService;
@ResponseBody
@RequestMapping("/buy")
public String buy(){
return orderService.goBuy("12345678");
}
}
@Service
public class OrderService {
public String goBuy(String orderId){
return "orderId===="+orderId;
}
}
-
Run/Debug Configurations
測(cè)試結(jié)果：
4.2 定制SpringMVC
現(xiàn)在使用配置注解，定制我們的springmvc,可看官網(wǎng)描述梆造，加入@EnableWebMvc,來(lái)定制配置功能缴守。
- 直接在JamesAppConfig實(shí)現(xiàn)WebMvcConfigurer。
@ComponentScan(value="com.wangzhen",includeFilters={
@ComponentScan.Filter(type=FilterType.ANNOTATION,classes={Controller.class})
},useDefaultFilters=false)
@EnableWebMvc
public class JamesAppConfig extends WebMvcConfigurerAdapter {
//定制視圖解析器
@Override
public void configureViewResolvers(ViewResolverRegistry registry) {
//比如我們想用JSP解析器,默認(rèn)所有的頁(yè)面都從/WEB-INF/AAA.jsp
registry.jsp("/WEB-INF/pages/",".jsp");
}
}
- 新建目錄src/main/webapp/WEB-INF/pages镇辉，添加ok.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>ok</title>
</head>
<body>
successful!
</body>
</html>
- 在OrderController控制類(lèi)加一個(gè)解析器的定制頁(yè)面返回
//相當(dāng)于找 /WEB-INF/pages/ok.jsp
@RequestMapping("/ok")
public String ok(){
return "ok";
}
-
測(cè)試結(jié)果
-
出現(xiàn)的問(wèn)題
解決方法：配置springmvclearn.iml
4.同步和異步處理
4.1 同步處理
客戶端發(fā)出請(qǐng)求后屡穗，一直等待服務(wù)端響應(yīng)。
- 修改JamesServlet忽肛，測(cè)試
@WebServlet("/order")
public class JamesServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println(Thread.currentThread()+ "start...");
try {
buyCards();
} catch (Exception e) {
e.printStackTrace();
}
resp.getWriter().write("order successful...");
System.out.println(Thread.currentThread() + "end...");
}
public void buyCards() throws InterruptedException{
System.out.println(Thread.currentThread()+".............");
Thread.sleep(5000);//模擬業(yè)務(wù)操作
}
}
結(jié)果：
Thread[http-nio-8080-exec-2,5,main]start...
Thread[http-nio-8080-exec-2,5,main].............
Thread[http-nio-8080-exec-2,5,main]end...
從頭到尾都是由同一個(gè)線程2進(jìn)行處理的鸡捐，線程從頭執(zhí)行到尾，會(huì)造成資源占用不能釋放麻裁。
4.2 異步請(qǐng)求
@WebServlet(value="/asyncOrder", asyncSupported = true)
public class OrderAsyncServlet extends HttpServlet{
//支持異步處理asyncSupported = true
//重寫(xiě)doget方法
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//151個(gè)……
System.out.println("主線程開(kāi)始……"+Thread.currentThread()+"start....."+System.currentTimeMillis());
AsyncContext startAsync = req.startAsync();
startAsync.start(new Runnable() {
@Override
public void run() {
try {
System.out.println("副線程開(kāi)始……"+Thread.currentThread()+"start....."+System.currentTimeMillis());
buyCards();
startAsync.complete();
AsyncContext asyncContext = req.getAsyncContext();
ServletResponse response = asyncContext.getResponse();
response.getWriter().write("order sucesful....");
System.out.println("副線程結(jié)束……"+Thread.currentThread()+"end....."+System.currentTimeMillis());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
System.out.println("主線程結(jié)束……"+Thread.currentThread()+"end....."+System.currentTimeMillis());
//主線程的資源斷開(kāi)……
}
public void buyCards() throws InterruptedException{
System.out.println(Thread.currentThread()+".............");
Thread.sleep(5000);//模擬業(yè)務(wù)操作
}
}
報(bào)錯(cuò)：
Exception in thread "http-nio-8080-exec-4" java.lang.IllegalStateException: It is illegal to call this method if the current request is not in asynchronous mode (i.e. isAsyncStarted() returns false)
at org.apache.catalina.connector.Request.getAsyncContext(Request.java:1758)
at org.apache.catalina.connector.RequestFacade.getAsyncContext(RequestFacade.java:1068)
at com.wangzhen.servlet.OrderAsyncServlet$1.run(OrderAsyncServlet.java:38)
at org.apache.catalina.core.AsyncContextImpl$RunnableWrapper.run(AsyncContextImpl.java:515)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:844)
原因：AsyncContext.complete();方法的調(diào)用時(shí)機(jī)錯(cuò)誤箍镜，應(yīng)該在子線程完全處理完成業(yè)務(wù)邏輯的最后調(diào)用源祈。
修改：
System.out.println("副線程開(kāi)始……"+Thread.currentThread()+"start....."+System.currentTimeMillis());
buyCards();
AsyncContext asyncContext = req.getAsyncContext();
ServletResponse response = asyncContext.getResponse();
response.getWriter().write("order sucesful....");
startAsync.complete();
System.out.println("副線程結(jié)束……"+Thread.currentThread()+"end....."+System.currentTimeMillis());
結(jié)果：
主線程開(kāi)始……Thread[http-nio-8080-exec-6,5,main]start.....1536967088156
主線程結(jié)束……Thread[http-nio-8080-exec-6,5,main]end.....1536967088172
副線程開(kāi)始……Thread[http-nio-8080-exec-6,5,main]start.....1536967088173
Thread[http-nio-8080-exec-6,5,main].............
副線程結(jié)束……Thread[http-nio-8080-exec-6,5,main]end.....1536967093173
4.3 SpringMVC的異步請(qǐng)求
4.3.1 異步order01
@Controller
public class AsyncOrderController {
@ResponseBody
@RequestMapping("/order01")
public Callable<String> order01(){
System.out.println("主線程開(kāi)始..."+Thread.currentThread()+"==>"+System.currentTimeMillis());
Callable<String> callable = new Callable<String>() {
@Override
public String call() throws Exception {
System.out.println("副線程開(kāi)始..."+Thread.currentThread()+"==>"+System.currentTimeMillis());
Thread.sleep(2000);
System.out.println("副線程開(kāi)始..."+Thread.currentThread()+"==>"+System.currentTimeMillis());
return "order buy successful........";
}
};
System.out.println("主線程結(jié)束..."+Thread.currentThread()+"==>"+System.currentTimeMillis());
return callable;
}
}
結(jié)果：
Thread[http-nio-8080-exec-4,5,main]----preHandle-------------/springmvclearn/order01
主線程開(kāi)始...Thread[http-nio-8080-exec-4,5,main]==>1536970626335
主線程結(jié)束...Thread[http-nio-8080-exec-4,5,main]==>1536970626341
副線程開(kāi)始...Thread[MvcAsync1,5,main]==>1536970626352
副線程開(kāi)始...Thread[MvcAsync1,5,main]==>1536970628353
Thread[http-nio-8080-exec-5,5,main]----preHandle-------------/springmvclearn/order01
Thread[http-nio-8080-exec-5,5,main]----postHandle-------------
Thread[http-nio-8080-exec-5,5,main]----afterCompletion-------------
4.3.2 訂單示例
需求描述：以創(chuàng)建訂單為例，tomcat啟動(dòng)線程1來(lái)完成一個(gè)請(qǐng)求色迂，但實(shí)際上是訂單服務(wù)才能創(chuàng)建訂單香缺，那么tomcat線程應(yīng)該把請(qǐng)求轉(zhuǎn)發(fā)給訂單服務(wù)，使用消息中間件來(lái)處理歇僧，訂單服務(wù)把處理結(jié)果也放到消息中間件图张，由tomcat的線程N(yùn)拿到結(jié)果后，響應(yīng)給客戶端诈悍。
- 創(chuàng)建隊(duì)列
public class JamesDeferredQueue {
private static Queue<DeferredResult<Object>> queue = new ConcurrentLinkedQueue<DeferredResult<Object>>();
public static void save(DeferredResult<Object> deferredResult){
queue.add(deferredResult);
}
public static DeferredResult<Object> get( ){
return queue.poll();
}
}
- 模擬兩個(gè)線程/createOrder和/get
@Controller
public class AsyncOrderController {
//其實(shí)相當(dāng)于我們說(shuō)的tomcat的線程1祸轮，來(lái)處理用戶請(qǐng)求，并將請(qǐng)求的操作放到Queue隊(duì)列里
@ResponseBody
@RequestMapping("/createOrder")
public DeferredResult<Object> createOrder(){
DeferredResult<Object> deferredResult = new DeferredResult<>((long)5000, "create fail...");
JamesDeferredQueue.save(deferredResult);
return deferredResult;
}
@ResponseBody
@RequestMapping("/get")
public String get(){
String order = UUID.randomUUID().toString();
DeferredResult<Object> deferredResult = JamesDeferredQueue.get();
deferredResult.setResult(order);
JamesDeferredQueue.save(deferredResult);
return "get method order = " + order;
}
}
測(cè)試結(jié)果：
超過(guò)5s沒(méi)有g(shù)et
正常情況
參考
- 1）Java servlet3.1官方參考文檔
- 2）注解實(shí)現(xiàn)SpringMVC異步處理中的問(wèn)題
- 3）SpringMVC官方參考文檔
- 4）享學(xué)課堂James老師筆記
