基于Idea构建Tomcat源码及问题解决

- 日理万妓 2023-07-18 02:58 13阅读 0赞

## 1.前言 ##

最近在项目中有一个想法，要是项目中能通过网页热部署一些二次开发的模块，那应该是一件很有意思而且很有实际作用的功能。所以想到了Tomcat中类加载器中反委派机制做法。为了更深入了解tomcat类加载器的反委派机制的具体实现，需要搭建Tomcat源码环境。虽然不是很难，但是还有避免不了一些坑，依次记载，方便大家学习交流。

## 2.环境准备 ##

### 2.1 Idea环境 ###

本次Idea版本采用比较稳定的IntelliJIDEA2018.2.1。

### 2.2 JDK版本 ###

JDK版本为1.8.0.131\_x64。

### 2.3 Tomcat版本 ###

本次tomcat版本采用tomcat7.0.103。可以通过在官网下载。注意，此处应该选择Source Code Distributions。下载的格式为zip。

https://tomcat.apache.org/download-70.cgi

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29ZaW5IZVpoaUd1YW5n_size_16_color_FFFFFF_t_70][]

## 3.源码部署 ##

### 3.1 解压zip压缩包，此处简单，一句带过。 ###

### 3.2 通过idea导入此项目 ###

依次选择【Open -->选择刚才解压的文件夹】。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29ZaW5IZVpoaUd1YW5n_size_16_color_FFFFFF_t_70 1][]

### 3.3 指定jdk,工程语言级别以及编译输出路径 ###

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29ZaW5IZVpoaUd1YW5n_size_16_color_FFFFFF_t_70 2][]

### 3.4 指定src以及test路径 ###

将java指定为【Sources Root】，将test指定为【Test Sources Root】,具体操作如下:

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29ZaW5IZVpoaUd1YW5n_size_16_color_FFFFFF_t_70 3][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29ZaW5IZVpoaUd1YW5n_size_16_color_FFFFFF_t_70 4][]

### 3.5 引入Jar包 ###

此时，我们发现有部分代码飘红，说明需要引入部分jar包，如下图。

![20200323212459690.png][]

为了方便大家构建项目，这里我们通过maven将依赖的jar包引导到工程中去。下文是我整理好的pom.xml文件。

<?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>
    
        <groupId>cn.surpass</groupId>
        <artifactId>tomcat</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>tomcat</name>
        <properties>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.apache.ant</groupId>
                <artifactId>ant</artifactId>
                <version>1.10.7</version>
            </dependency>
            <dependency>
                <groupId>org.eclipse.jdt</groupId>
                <artifactId>org.eclipse.jdt.core</artifactId>
                <version>3.20.0</version>
            </dependency>
            <dependency>
                <groupId>wsdl4j</groupId>
                <artifactId>wsdl4j</artifactId>
                <version>1.6.3</version>
            </dependency>
    
            <dependency>
                <groupId>javax.xml</groupId>
                <artifactId>jaxrpc</artifactId>
                <version>1.1</version>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
            </dependency>
            <dependency>
                <groupId>org.hamcrest</groupId>
                <artifactId>hamcrest-core</artifactId>
                <version>1.3</version>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>jmock</groupId>
                <artifactId>jmock</artifactId>
                <version>1.2.0</version>
            </dependency>
            <dependency>
                <groupId>org.jmock</groupId>
                <artifactId>jmock</artifactId>
                <version>2.12.0</version>
            </dependency>
            <dependency>
                <groupId>org.easymock</groupId>
                <artifactId>easymock</artifactId>
                <version>4.2</version>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>org.eclipse.jdt.core.compiler</groupId>
                <artifactId>ecj</artifactId>
                <version>4.4.2</version>
            </dependency>
        </dependencies>
    </project>

**3.5.1 将pom.xml文件拷贝到tomcat的文件夹下。**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29ZaW5IZVpoaUd1YW5n_size_16_color_FFFFFF_t_70 5][]

**3.5.2 编程maven工程，引入pom.xml文件**

选择idea右侧的选项卡【Maven Projects】，然后点击【+】，现在刚才拷贝进去的pom.xml文件，在弹出的点击【import changes】，此操作对于熟悉idea的读者并不陌生，可以直接略过。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29ZaW5IZVpoaUd1YW5n_size_16_color_FFFFFF_t_70 6][]

![20200323213046953.png][]

此时，我们发现之前飘红的已经消失了。

### 3.6 运行tomcat启动文件 ###

我们通过路径找到类文件org.apache.catalina.startup.Bootstrap。熟悉idea的朋友知道，双击shift键，输入Bootstrap可以快速定位。接下来我们运行此类。很不幸，发现缺少一个类。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29ZaW5IZVpoaUd1YW5n_size_16_color_FFFFFF_t_70 7][]

通过此类分析，这个类并没有在import导入，所以我们猜想这个CookieFilter类应该和TestCookieFilter在同一个全类路径，即在util包下。为了方便大家学习，我也把这个文件分享出来，然后把此类放到$\{tomcat\}\\test\\util下。

/*
     * Licensed to the Apache Software Foundation (ASF) under one or more
     * contributor license agreements.  See the NOTICE file distributed with
     * this work for additional information regarding copyright ownership.
     * The ASF licenses this file to You under the Apache License, Version 2.0
     * (the "License"); you may not use this file except in compliance with
     * the License.  You may obtain a copy of the License at
     *
     *     http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    package util;
    
    import java.util.Locale;
    import java.util.StringTokenizer;
    
    /**
     * Processes a cookie header and attempts to obfuscate any cookie values that
     * represent session IDs from other web applications. Since session cookie names
     * are configurable, as are session ID lengths, this filter is not expected to
     * be 100% effective.
     *
     * It is required that the examples web application is removed in security
     * conscious environments as documented in the Security How-To. This filter is
     * intended to reduce the impact of failing to follow that advice. A failure by
     * this filter to obfuscate a session ID or similar value is not a security
     * vulnerability. In such instances the vulnerability is the failure to remove
     * the examples web application.
     */
    public class CookieFilter {
    
        private static final String OBFUSCATED = "[obfuscated]";
    
        private CookieFilter() {
            // Hide default constructor
        }
    
        public static String filter(String cookieHeader, String sessionId) {
    
            StringBuilder sb = new StringBuilder(cookieHeader.length());
    
            // Cookie name value pairs are ';' separated.
            // Session IDs don't use ; in the value so don't worry about quoted
            // values that contain ;
            StringTokenizer st = new StringTokenizer(cookieHeader, ";");
    
            boolean first = true;
            while (st.hasMoreTokens()) {
                if (first) {
                    first = false;
                } else {
                    sb.append(';');
                }
                sb.append(filterNameValuePair(st.nextToken(), sessionId));
            }
    
    
            return sb.toString();
        }
    
        private static String filterNameValuePair(String input, String sessionId) {
            int i = input.indexOf('=');
            if (i == -1) {
                return input;
            }
            String name = input.substring(0, i);
            String value = input.substring(i + 1, input.length());
    
            return name + "=" + filter(name, value, sessionId);
        }
    
        public static String filter(String cookieName, String cookieValue, String sessionId) {
            if (cookieName.toLowerCase(Locale.ENGLISH).contains("jsessionid") &&
                    (sessionId == null || !cookieValue.contains(sessionId))) {
                cookieValue = OBFUSCATED;
            }
    
            return cookieValue;
        }
    }

### 3.7 运行tomcat启动文件 ###

此时我们在运行此类，发现运行成功。随后我们在网页打开http://127.0.0.1:8080验证是否启动成功。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29ZaW5IZVpoaUd1YW5n_size_16_color_FFFFFF_t_70 8][]

## 4 修改乱码 ##

不知道上面读者是否发现在输出日志的控制台中发生了乱码。

![20200323215311586.png][]

其实解决问题的思路很简单，我们需要修改两个类。

### 4.1 org.apache.tomcat.util.res.StringManager ###

代码如插入位置如下图

try{
        value = new String(value.getBytes("ISO-8859-1"),"UTF-8");
    }catch (Exception e){}

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29ZaW5IZVpoaUd1YW5n_size_16_color_FFFFFF_t_70 9][]

### 4.2 org.apache.jasper.compiler.Localizer ###

代码如插入位置如下图

try{
        errMsg = new String(errMsg.getBytes("ISO-8859-1"),"UTF-8");
    }catch (Exception e){}

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29ZaW5IZVpoaUd1YW5n_size_16_color_FFFFFF_t_70 10][]

4.3 此时我们再次运行，发现乱码不见了。

![20200323215840141.png][]

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