一、下载Tomcat7源码
从官网上下载Tomcat源码， http://mirror.bit.edu.cn/apache/tomcat/tomcat-7/v7.0.70/src/apache-tomcat-7.0.70-src.zip
下载之后，将源码解压后重名为tomcat-src，放在E盘的tomcat7目录下.
二、安装Ant
因Tomcat源码需要ant编译，所以需要安装Ant，从官网下载后解压，并配置环境变量即可.
三、安装JDK6
tomcat7的编译需要JDK6的环境，JDK7以及以上,ant 编译时会报错.
四、用Ant工具编译Tomcat源码
打开cmd命令行工具，进入tomcat源码目录，输入ant ide-eclipse ，然后按下Enter键，会自动下载编译需要的依赖包.
testexist:
[echo] Testing for C:\Users\yulei/tomcat-build-libs/objenesis-1.2/objenesis-1.2.jar downloadzip:
[get] Getting: https://objenesis.googlecode.com/files/objenesis-1.2-bin.zip
[get] To: C:\Users\yulei\tomcat-build-libs\download-1649634615.zip
[get] Error getting https://objenesis.googlecode.com/files/objenesis-1.2-bin.zip to C:\Users\yulei\tomcat-build-libs\download-16496 BUILD FAILED
E:\tomcat7\tomcat_src\build.xml:2697: The following error occurred while executing this line:
E:\tomcat7\tomcat_src\build.xml:2848: java.net.ConnectException: Connection timed out: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:529)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:570)
at com.sun.net.ssl.internal.ssl.BaseSSLSocketImpl.connect(BaseSSLSocketImpl.java:141)
at sun.net.NetworkClient.doConnect(NetworkClient.java:163)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:411)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:525)
at sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:272)
at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:329)
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:172)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:923)
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:158)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:133)
at org.apache.tools.ant.taskdefs.Get$GetThread.openConnection(Get.java:728)
at org.apache.tools.ant.taskdefs.Get$GetThread.get(Get.java:641)
at org.apache.tools.ant.taskdefs.Get$GetThread.run(Get.java:631) Total time: 1 minute 58 seconds
可以看见，编译报错了，是因为从国外网站下载依赖的objenesis-1.2-bin.zip超时了，导致编译失败.
解决办法，*下载objenesis-1.2-bin.zip文件，这里为了方便，为大家提供了下载地址：http://pan.baidu.com/s/1kUWtA8v
将其解压后放在C:\Users\yulei\tomcat-build-libs 目录下面
再次运行ant ide-eclipse 命名就会编译成功了
编译成功后，会生成Eclipse的项目文件(.classpath等),如下图：
五、将Tomcat7源码导入MyEclipse
以此类推，把余下的Tomacat依赖包配置好。TOMCAT_LIB_BASE 配置的地址是：C:/Users/yulei/tomcat-build-libs
六、运行Tomcat
右键Tomcat工程，Run As --->Java Application, 选择Bootstrap.
点击OK，出现如下选项：
选择start-tomcat，后命令行出现如下信息：
九月 05, 2016 11:21:21 下午 org.apache.catalina.startup.CatalinaProperties loadProperties
WARNING: Failed to load catalina.properties
九月 05, 2016 11:21:21 下午 org.apache.catalina.startup.Catalina load
WARNING: Unable to load server configuration from [D:\CBSS\code\tomcat-7.0.x\output\build\conf\server.xml]
九月 05, 2016 11:21:21 下午 org.apache.catalina.startup.Catalina load
WARNING: Unable to load server configuration from [D:\CBSS\code\tomcat-7.0.x\output\build\conf\server.xml]
九月 05, 2016 11:21:21 下午 org.apache.catalina.startup.Catalina start
SEVERE: Cannot start server. Server instance is not configured.
表示，tomcat服务没有跑起来，别着急，用Ant deploy一下你的tomcat工程.
deploy成功之后，然后再运行你的tomcat，会出现如下信息，表示Tomcat服务已成功启起来：
访问http://localhost:8080
