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實戰Tomcat映象

TomCat目錄結構說明

#TomCat目錄結構說明:
bin:該目錄存放TomCat二進位制可執行檔案,常用的有startup.bat和shutdown.bat檔案,startup.bat用來啟動Tomcat,shutdown.bat用來停止Tomcat;
conf:TomCat伺服器的配置目錄,主要有server.xml(配置伺服器資訊,如修改埠號,新增虛擬主機等)、tomcat-users.xml(TomCat使用者與角色資訊,對TomCat後臺管理)和web.xml(Web專案部署描述符檔案);
lib:Tomcat所需的jar包;
logs:存放TomCat的日誌檔案;
temp:存放Tomcat的臨時檔案;
webapps:存放所部署的Web專案;
work:存放Web專案部署執行時生成的檔案,如java和class檔案;
RUNNING.txt:可檢視如何配置TomCat環境變數。

#TomCat配置環境變數

Tomcat是Java應用程式,不直接使用環境變數。
環境變數由Tomcat啟動指令碼使用。指令碼使用
環境變數來準備啟動Tomcat的命令。

(3.1)設定CATALINA_HOME(必填)和CATALINA_BASE(可選)

CATALINA_HOME環境變數應設定為
Tomcat“二進位制”分發的根目錄。

Tomcat啟動指令碼具有一些邏輯來設定此變數
如果不存在,則根據啟動指令碼的位置自動進行
在* nix中和Windows的當前目錄中。該邏輯可能不起作用在所有情況下,建議顯式設定變數。

CATALINA_BASE環境變數指定根的位置
Tomcat“活動配置”的目錄。它是可選的。它預設等於CATALINA_HOME。
#jdk目錄結構說明

bin目錄:Java工具的可執行檔案,包括: java、Java編譯器javac、反編譯.class檔案javap、金鑰管理工具keytool、Java文件工具javadoc等。
COPYRIGHT檔案:版權資訊。
db目錄:Java實現的資料庫。
include目錄:.h標頭檔案,C語言開發時用到的標頭檔案。比如jni.h是開發jni程式時必須引用的標頭檔案。
lib目錄: Java類庫,我們經常看到的dt.jar和tools.jar就在這個目錄下。
src.zip檔案:Java類庫原始碼,包括了rt.jar庫中的關鍵部分;除了Java類庫,還包含了啟動器(launcher)的原始碼(C語言實現)。
jre目錄:Java執行環境。

#jdk配置環境變數

JDK安裝完成後,首先要配置JAVA_HOME變數,JAVA_HOME變數指向JDK的安裝目錄,配置JAVA_HOME主要目的是: 
(1)配置其它JDK環境變數時,可以方便地引用JDK的安裝目錄。

(2)JDK安裝完成後,需要配置Path環境變數,以方便開發者執行Java編譯器等程式。開發者不管是用整合開發工具還是文字編輯工具編寫Java程式時,當整合開發工具呼叫Java編譯器或使用者在Windows 命令列視窗輸入命令執行Java編譯器時,作業系統需要從Path環境變數獲取Java編譯器等程式所在目錄並啟動執行。例如:假設Java整合開發工具或Windows 命令列視窗的當前工作目錄和Java編譯器所在目錄不同,開發者又沒有在path環境變數中配置Java編譯器所在目錄的路徑,作業系統就找不到Java編譯器程式,也就無法啟動Java編譯器程式進行編譯工作。

(3)Java原始碼被被編譯後形成副檔名為“.class”的檔案,JVM(Java虛擬機器)執行Java 程式時,需要載入已被編譯的“.class”的檔案以及該“.class”檔案匯入的其它類(如Java的System類)。設定CLASSPATH的目的就是讓JVM能夠通過CLASSPATH設定的路徑找到這些類檔案

ENV CLASSPATH $JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
告訴jvm要使用或執行的class放在什麼路徑上,便於JVM載入class檔案,.;表示當前路徑,tools.jar和dt.jar為類庫路徑。

CLASSPATH詳解:
tools.jar
	工具類庫(編譯和執行等),它跟我們程式中用到的基礎類庫沒有關係。我們注意到在Path中變數值bin目錄下的各個exe工具的大小都很小,一般都在27KB左右,這是因為它們實際上僅僅相當於是一層程式碼的包裝,這些工具的實現所要用到的類庫都在tools.jar中,用壓縮軟體開啟tools.jar,你會發現有很多檔案是和bin目錄下的exe工具相對性的,檢視圖一。當然,如果tools.jar的功能只有這些的話,那麼我們根本不用把它加入到CLASSPATH變數中,因為bin目錄下的工具自己可以完成對這些類庫的呼叫,因此tools.jar應該還有其他的功能。在裡面還可以看到有Applet和RMI等相關的檔案,因此tools.jar應該還是遠端呼叫等必須的jar包。tools.jar的其他作用可以檢視其他資料。

dt.jar
	執行環境類庫,主要是Swing包,這一點通過用壓縮軟體開啟dt.jar也可以看到。如果在開發時候沒有用到Swing包,那麼可以不用將dt.jar新增到CLASSPATH變數中。

CLASSPATH中的類庫是由Application ClassLoader或者我們自定義的類載入器來載入的,這裡當然不能包括基礎類庫,如果包括基礎類庫的話,並用兩個不同的自定義類載入器去載入該基礎類,那它得到的該基礎類就不是唯一的了,這樣便不能保證Java類的安全性。

基本類庫和擴充套件類庫rt.jar
	基本類庫是所有的 import java.* 開頭的類,在 %JAVA_HOME%\jre\lib 目錄下(如其中的 rt.jar、resource.jar ),類載入機制提到,該目錄下的類會由 Bootstrap ClassLoader 自動載入,並通過親委派模型保證了基礎類庫只會被Bootstrap ClassLoader載入,這也就保證了基礎類的唯一性。
	擴充套件類庫是所有的 import javax.* 開頭的類,在 %JAVA_HOME%\jre\lib\ext 目錄下,該目錄下的類是由Extension ClassLoader 自動載入,不需要我們指定。

準備映象檔案

準備映象檔案、tomcat壓縮包、jdk壓縮包。

apache-tomcat-9.0.39.tar
jdk-8u271-linux-x64.tar

編寫Dockerfile檔案

官方命名:Dockerfile,build會自動尋找這個檔案,就不需要-f指定了!

容器內部/usr/local目錄下就會看到readme.txt這個檔案
將壓縮包新增進去 跟解壓路徑
注:用ADD命令新增進去的.tar.gz檔案會自動解壓
安裝基礎的命令
設定ENV環境變數 進去的時候就進入到環境變數
配置工作目錄

配置JAVA環境變數

配置Tomcat環境變數

暴露埠

FROM centos
MAINTAINER lwenwu<[email protected]>

COPY readme.txt /usr/local/readme.txt

ADD jdk-8u271-linux-x64.tar.gz /usr/local
ADD apache-tomcat-9.0.39.tar.gz /usr/local

RUN yum -y install vim

ENV MYPATH /usr/local
WORKDIR $MYPATH

ENV JAVA_HOME /usr/local/jdk1.8.0_271
ENV CLASSPATH $JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar

ENV CATALINA_HOME /usr/local/apache-tomcat-9.0.39
ENV CATALINA_BASE /usr/local/apache-tomcat-9.0.39
ENV PATH $PATH:$JAVA_HOME/bin:$CATALINA_HOME/lib:$CATALINA_HOME/bin

EXPOSE 8080

CMD /usr/local/apache-tomcat-9.0.39/bin/startup.sh && tail -F /usr/local/apache-tomcat-9.0.39/logs/catalina.out

構建映象

docker build -t diytomcat .

構建過程

[root@localhost dockerfile]# docker build -t testtomcat .
Sending build context to Docker daemon  154.4MB
Step 1/15 : FROM centos
latest: Pulling from library/centos
3c72a8ed6814: Pull complete 
Digest: sha256:76d24f3ba3317fa945743bb3746fbaf3a0b752f10b10376960de01da70685fbd
Status: Downloaded newer image for centos:latest
 ---> 0d120b6ccaa8
Step 2/15 : MAINTAINER lwenwu<[email protected]>
 ---> Running in 47b5eb8df66b
Removing intermediate container 47b5eb8df66b
 ---> 49bcdfea4e32
Step 3/15 : COPY readme.txt /usr/local/readme.txt
 ---> 2a6be7198e44
Step 4/15 : ADD jdk-8u271-linux-x64.tar.gz /usr/local
 ---> 88e1646ee66d
Step 5/15 : ADD apache-tomcat-9.0.39.tar.gz /usr/local
 ---> 259ee757cb6f
Step 6/15 : RUN yum -y install vim
 ---> Running in 2d1b5f504afa
CentOS-8 - AppStream                            3.3 MB/s | 5.8 MB     00:01    
CentOS-8 - Base                                 2.5 MB/s | 2.2 MB     00:00    
CentOS-8 - Extras                                13 kB/s | 8.1 kB     00:00    
Dependencies resolved.
================================================================================
 Package             Arch        Version                   Repository      Size
================================================================================
Installing:
 vim-enhanced        x86_64      2:8.0.1763-13.el8         AppStream      1.4 M
Installing dependencies:
 gpm-libs            x86_64      1.20.7-15.el8             AppStream       39 k
 vim-common          x86_64      2:8.0.1763-13.el8         AppStream      6.3 M
 vim-filesystem      noarch      2:8.0.1763-13.el8         AppStream       48 k
 which               x86_64      2.21-12.el8               BaseOS          49 k

Transaction Summary
================================================================================
Install  5 Packages

Total download size: 7.8 M
Installed size: 31 M
Downloading Packages:
(1/5): gpm-libs-1.20.7-15.el8.x86_64.rpm        176 kB/s |  39 kB     00:00    
(2/5): vim-filesystem-8.0.1763-13.el8.noarch.rp 697 kB/s |  48 kB     00:00    
(3/5): which-2.21-12.el8.x86_64.rpm             474 kB/s |  49 kB     00:00    
(4/5): vim-enhanced-8.0.1763-13.el8.x86_64.rpm  1.6 MB/s | 1.4 MB     00:00    
(5/5): vim-common-8.0.1763-13.el8.x86_64.rpm    4.2 MB/s | 6.3 MB     00:01    
--------------------------------------------------------------------------------
Total                                           2.2 MB/s | 7.8 MB     00:03     
warning: /var/cache/dnf/AppStream-02e86d1c976ab532/packages/gpm-libs-1.20.7-15.el8.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID 8483c65d: NOKEY
CentOS-8 - AppStream                            825 kB/s | 1.6 kB     00:00    
Importing GPG key 0x8483C65D:
 Userid     : "CentOS (CentOS Official Signing Key) <[email protected]>"
 Fingerprint: 99DB 70FA E1D7 CE22 7FB6 4882 05B5 55B3 8483 C65D
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial
Key imported successfully
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                        1/1 
  Installing       : which-2.21-12.el8.x86_64                               1/5 
  Installing       : vim-filesystem-2:8.0.1763-13.el8.noarch                2/5 
  Installing       : vim-common-2:8.0.1763-13.el8.x86_64                    3/5 
  Installing       : gpm-libs-1.20.7-15.el8.x86_64                          4/5 
  Running scriptlet: gpm-libs-1.20.7-15.el8.x86_64                          4/5 
  Installing       : vim-enhanced-2:8.0.1763-13.el8.x86_64                  5/5 
  Running scriptlet: vim-enhanced-2:8.0.1763-13.el8.x86_64                  5/5 
  Running scriptlet: vim-common-2:8.0.1763-13.el8.x86_64                    5/5 
  Verifying        : gpm-libs-1.20.7-15.el8.x86_64                          1/5 
  Verifying        : vim-common-2:8.0.1763-13.el8.x86_64                    2/5 
  Verifying        : vim-enhanced-2:8.0.1763-13.el8.x86_64                  3/5 
  Verifying        : vim-filesystem-2:8.0.1763-13.el8.noarch                4/5 
  Verifying        : which-2.21-12.el8.x86_64                               5/5 

Installed:
  gpm-libs-1.20.7-15.el8.x86_64         vim-common-2:8.0.1763-13.el8.x86_64    
  vim-enhanced-2:8.0.1763-13.el8.x86_64 vim-filesystem-2:8.0.1763-13.el8.noarch
  which-2.21-12.el8.x86_64             

Complete!
Removing intermediate container 2d1b5f504afa
 ---> 104e56b60aec
Step 7/15 : ENV MYPATH /usr/local
 ---> Running in 9582f9a31cee
Removing intermediate container 9582f9a31cee
 ---> dd0e414f6f83
Step 8/15 : WORKDIR $MYPATH
 ---> Running in 5a1b9e7b62c7
Removing intermediate container 5a1b9e7b62c7
 ---> 4a2e99caa954
Step 9/15 : ENV JAVA_HOME /usr/local/jdk1.8.0_271
 ---> Running in 4d8ee0c67b7b
Removing intermediate container 4d8ee0c67b7b
 ---> 8da62fbac351
Step 10/15 : ENV CLASSPATH $JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
 ---> Running in 065821bf046e
Removing intermediate container 065821bf046e
 ---> ad73e38ee464
Step 11/15 : ENV CATALINA_HOME /usr/local/apache-tomcat-9.0.39
 ---> Running in 4792108504fd
Removing intermediate container 4792108504fd
 ---> e5ad1371c5c4
Step 12/15 : ENV CATALINA_BASE /usr/local/apache-tomcat-9.0.39
 ---> Running in 62dbef974ce0
Removing intermediate container 62dbef974ce0
 ---> a494ad3353e3
Step 13/15 : ENV PATH $PATH:$JAVA_HOME/bin:$CATALINA_HOME/lib:$CATALINA_HOME/bin
 ---> Running in 2cc75de94c1e
Removing intermediate container 2cc75de94c1e
 ---> 06bec94756ec
Step 14/15 : EXPOSE 8080
 ---> Running in ccbe33eefb43
Removing intermediate container ccbe33eefb43
 ---> 75e040b2f7c3
Step 15/15 : CMD /usr/local/apache-tomcat-9.0.39/bin/startup.sh && tail -F /usr/local/apache-tomcat-9.0.39/logs/catalina.out
 ---> Running in ad622bea20ad
Removing intermediate container ad622bea20ad
 ---> 13aa57b24d7f
Successfully built 13aa57b24d7f
Successfully tagged testtomcat:latest

檢視映象

docker images

後臺執行容器

-d:後臺執行

掛載目錄

docker run -d -p 9090:8080 --name tomcattest -v /data/tomcat/test:/usr/local/apache-tomcat-9.0.39/webapps/test -v /data/tomcat/logs:/usr/local/apache-tomcat-9.0.39/logs testtomcat

測試掛載

容器內:

容器外:

進入容器

檢視執行容器

docker ps


進入容器

docker exec -it ID /bin/bash

訪問測試

容器外面測試

curl localhost:9090
[root@localhost data]# curl localhost:9090



<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <title>Apache Tomcat/9.0.39</title>
        <link href="favicon.ico" rel="icon" type="image/x-icon" />
        <link href="favicon.ico" rel="shortcut icon" type="image/x-icon" />
        <link href="tomcat.css" rel="stylesheet" type="text/css" />
    </head>

    <body>
        <div id="wrapper">
            <div id="navigation" class="curved container">
                <span id="nav-home"><a href="https://tomcat.apache.org/">Home</a></span>
                <span id="nav-hosts"><a href="/docs/">Documentation</a></span>
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                <span id="nav-examples"><a href="/examples/">Examples</a></span>
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                <h1>Apache Tomcat/9.0.39</h1>
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                <div id="congrats" class="curved container">
                    <h2>If you're seeing this, you've successfully installed Tomcat. Congratulations!</h2>
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                    <img src="tomcat.png" alt="[tomcat logo]" />
                    <div id="tasks">
                        <h3>Recommended Reading:</h3>
                        <h4><a href="/docs/security-howto.html">Security Considerations How-To</a></h4>
                        <h4><a href="/docs/manager-howto.html">Manager Application How-To</a></h4>
                        <h4><a href="/docs/cluster-howto.html">Clustering/Session Replication How-To</a></h4>
                    </div>
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                <div id="actions">
                    <div class="button">
                        <a class="container shadow" href="/manager/status"><span>Server Status</span></a>
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                    <div class="container">
                        <p><a href="/docs/realm-howto.html">Realms &amp; AAA</a></p>
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            <div id="lower">
                <div id="low-manage" class="">
                    <div class="curved container">
                        <h3>Managing Tomcat</h3>
                        <p>For security, access to the <a href="/manager/html">manager webapp</a> is restricted.
                        Users are defined in:</p>
                        <pre>$CATALINA_HOME/conf/tomcat-users.xml</pre>
                        <p>In Tomcat 9.0 access to the manager application is split between
                           different users. &nbsp; <a href="/docs/manager-howto.html">Read more...</a></p>
                        <br />
                        <h4><a href="/docs/RELEASE-NOTES.txt">Release Notes</a></h4>
                        <h4><a href="/docs/changelog.html">Changelog</a></h4>
                        <h4><a href="https://tomcat.apache.org/migration.html">Migration Guide</a></h4>
                        <h4><a href="https://tomcat.apache.org/security.html">Security Notices</a></h4>
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                    <div class="curved container">
                        <h3>Documentation</h3>
                        <h4><a href="/docs/">Tomcat 9.0 Documentation</a></h4>
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                        <h4><a href="https://wiki.apache.org/tomcat/FrontPage">Tomcat Wiki</a></h4>
                        <p>Find additional important configuration information in:</p>
                        <pre>$CATALINA_HOME/RUNNING.txt</pre>
                        <p>Developers may be interested in:</p>
                        <ul>
                            <li><a href="https://tomcat.apache.org/bugreport.html">Tomcat 9.0 Bug Database</a></li>
                            <li><a href="/docs/api/index.html">Tomcat 9.0 JavaDocs</a></li>
                            <li><a href="https://github.com/apache/tomcat/tree/master">Tomcat 9.0 Git Repository at GitHub</a></li>
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                        <h3>Getting Help</h3>
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                        <p>The following mailing lists are available:</p>
                        <ul>
                            <li id="list-announce"><strong><a href="https://tomcat.apache.org/lists.html#tomcat-announce">tomcat-announce</a><br />
                                Important announcements, releases, security vulnerability notifications. (Low volume).</strong>
                            </li>
                            <li><a href="https://tomcat.apache.org/lists.html#tomcat-users">tomcat-users</a><br />
                                User support and discussion
                            </li>
                            <li><a href="https://tomcat.apache.org/lists.html#taglibs-user">taglibs-user</a><br />
                                User support and discussion for <a href="https://tomcat.apache.org/taglibs/">Apache Taglibs</a>
                            </li>
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            <p class="copyright">Copyright &copy;1999-2020 Apache Software Foundation.  All Rights Reserved</p>
        </div>
    </body>

</html>
[root@localhost data]#

網頁測試

http://192.168.100.100:9090


【坑】報錯日誌:

/usr/local/apache-tomcat-9.0.39/bin/catalina.sh: line 502: /usr/local/jdk.1.8.0.27/bin/java: No such file or directory
/usr/local/apache-tomcat-9.0.39/bin/catalina.sh: line 502: /usr/local/jdk.1.8.0.27/bin/java: No such file or directory

分析修改環境變數

#ENV JAVA_HOME /usr/local/jdk1.8.0_271		java環境變數錯誤,導致後面引用的變數都錯誤,最終導致Tomcat沒有啟動成功。

html測試

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                             http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         version="2.5">

</web-app>

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>hello.lwenwu!</title>
</head>
<body>
Hello World!<br/>
<%
out.println("this is a test file");
%>
</body>
</html>

失敗

分析: