加强1

42-44、类加载器

1】 Java虚拟机可以安装多个类加载器，系统默认的主要有三个，每个负责加载特定位置的类：

BootStrap、ExtClassLoader、AppClassLoader

2】 类加载器也是Java类，第一个加载器本身不是Java类，这正是BootStrap

3】 Java虚拟机中的所有类加载器采用具有父子关系的树形结构进行组织，在实例化每个类加载器对象时，需要为其指定一个父级加载器对象或默认采用系统加载器为其父级类加载。

4】 类加载器的委托机制

 A、首先当前线程的类加载器去加载线程中的第一个类

 如果类A中引用了B，java虚拟机将使用加载类A的类加载器来加载B

 还可以直接调用ClassLoader.loadClass()方法来指定某个类加载器加载某个类

B、每个类加载器加载类时，又先委托其上级类加载器。

  当所有祖宗类加载器没有加载到类，回到发起者类加载器，还加载不了，则抛出异常—ClassNotFoundException，不再去找发起者类加载器的儿子，因为没有getChild方法，即使有，那么多儿子，找哪一个呢？

 

 45、编写自己的类加载器

      自定义的类加载器必须继承ClassLoader

      覆盖findClass方法

      defineClass方法返回自定义类加载器的二进制代码

 

46、编写对class文件进行加密的工具类

 

 

需要加密的文件：

import

publicclassextends

   

public

return"hello ,itcast!"

}

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" string="" destdir="args[1];

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" fileinputstream="" fis="new" fileinputstream="" srcpath="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" string="" destfilename="srcPath.substring(srcPath.lastIndexOf('//')+1);

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" string="" destpath="destDir+'//'+destFileName;

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" fileoutputstream="" fos="new" fileoutputstream="" destpath="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" cypher="" fis="" fos="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" fis="" close="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" fos="" close="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 2" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 1" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" private="" static="" void="" cypher="" inputstream="" ips="" outputstream="" ops="" throws="" exception="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" int="" b="-1;

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" while="" b="ips.read())!=-1){

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 3" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" ops="" write="" b="" 0xff="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" size="2" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" font="" size="2" span="" lang="EN-US" font="" face="Times New Roman" 47-48="" font="" span="" font="" style="mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'" face="宋体" font="" font="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" font="" style="mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'" face="宋体" font="" size="2" font="" font="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" size="2" import="" java="" io="" bytearrayoutputstream="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" size="2" import="" java="" io="" fileinputstream="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" size="2" import="" java="" io="" filenotfoundexception="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" size="2" import="" java="" io="" fileoutputstream="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" size="2" import="" java="" io="" inputstream="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" size="2" import="" java="" io="" outputstream="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" size="2" public="" class="" myclassloader="" extends="" classloader="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" span="" style="mso-spacerun: yes" nbsp="" span="" param="" args="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" span="" style="mso-spacerun: yes" nbsp="" span="" throws="" filenotfoundexception="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" span="" style="mso-spacerun: yes" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" public="" static="" void="" main="" string="" args="" throws="" exception="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" string="" srcpath="args[0];

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" string="" destdir="args[1];

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" fileinputstream="" fis="new" fileinputstream="" srcpath="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" string="" destfilename="srcPath.substring(srcPath.lastIndexOf('//')+1);

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" string="" destpath="destDir+'//'+destFileName;

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" fileoutputstream="" fos="new" fileoutputstream="" destpath="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" cypher="" fis="" fos="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" fis="" close="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" fos="" close="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 2" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 1" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" private="" static="" void="" cypher="" inputstream="" ips="" outputstream="" ops="" throws="" exception="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" int="" b="-1;

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" while="" b="ips.read())!=-1){

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 3" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" ops="" write="" b="" 0xff="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 1" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" string="" classdir="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 1" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" override="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" protected="" class="" lt="" gt="" findclass="" string="" name="" throws="" classnotfoundexception="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" todo="" auto-generated="" method="" stub="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 2" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 2" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" string="" classfilename="classDir" name="" substring="" name="" lastindexof="" 1="" class="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" try="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 3" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" fileinputstream="" fis="new" fileinputstream="" classfilename="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 3" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" bytearrayoutputstream="" bos="new" bytearrayoutputstream="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 3" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" cypher="" fis="" bos="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 3" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" fis="" close="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 3" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" byte="" bytes="bos.toByteArray();

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 3" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" return="" defineclass="" bytes="" 0="" bytes="" length="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 3" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" catch="" exception="" e="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 3" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" todo="" auto-generated="" catch="" block="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 3" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" e="" printstacktrace="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" return="" super="" findclass="" name="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" public="" myclassloader="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" super="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" public="" myclassloader="" string="" classdir="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 3" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" this="" classdir="classDir;

" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" span="" style="mso-tab-count: 1" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" span="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 1" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 1" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 1" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" span="" style="mso-tab-count: 1" font="" face="Times New Roman" size="2" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" nbsp="" font="" span="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" font="" size="2" nbsp="" font="" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" span="" lang="EN-US" font="" face="Times New Roman" size="2" font="" span="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt" font="" style="mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'" face="宋体" font="" size="2" font="" font="" p="" p="" class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align="left" font="" face=""> 

java.util.Date; 

ClassLoaderAttachmentDate { 

@Override   String toString() {      ;   } 

 

 

运行类：

import

publicclass

      main(String[] args)Exception { 

           

new"itcastlib""classloader.ClassLoaderAttachment"

out

         } 

java.lang.reflect.Constructor;import

java.lang.reflect.Proxy;import

publicclass

      main(String[] args) { 

getProxyClass(Collection.classclass

out

for

new

'('

for

','

ifnulllength

')'

out

for

new

'('

for

','

ifnulllength

')'

out

          Constructor constructor = clazzProxy1.getConstructor(InvocationHandler.class);

          class  MyInvocationHandler1 implements InvocationHandler{

             @Override

                 return null;

          }

   

          proxy1.clear();      } 

 

 

52-54： InvocationHandler对象的内部功能及其原理

 

 

1】Client程序调用代理方法时，涉及三要素：objProxy对象，方法，参数

 

2】代理类对象的继承自java.lang.Object的方法，仅hashCode,quals,toString进行派发给handler，其他方法自己实现

3】动态代理原理图

proxy; 

java.lang.reflect.Constructor;import

java.lang.reflect.Method;import

java.util.ArrayList;import

publicclass

      main(String[] args)Exception  { 

getProxyClass(Collection.classclass

out

for

new

'('

for

','

ifnulllength

')'

out

for

new

'('

for

','

ifnulllength

')'

out

out"--------------------"

class

classimplements

@Override             Object invoke(Object proxy, Method method, Object[] args)Throwable {                 ;             }          }          Collection proxy1=(Collection)constructor.newInstance( MyInvocationHandler1());             System..println(proxy1.toString());          proxy1.clear();          

newProxyInstance(

class

newclass

new

                    ArrayList = ArrayList();                    

public

throws

longcurrentTimeMillis();

target

longcurrentTimeMillis();

out"running time:"

return

"lideguo"

"zahgnsd"

"tsdfesd"

"nidenia"

out

out

}package

import

java.lang.reflect.InvocationHandler;import

java.lang.reflect.Proxy;import

java.util.Collection; 

ProxyTest { 

publicstaticvoidthrows

      Class clazzProxy1=Proxy.getProxyClass(Collection..getClassLoader(),Collection.);      System..println(clazzProxy1.getName());            Constructor[] constructors=clazzProxy1.getConstructors();      (Constructor constructor: constructors){          String name=constructor.getName();          StringBuilder sBuilder= StringBuilder(name);          sBuilder.append();          Class[] clazzParams = constructor.getParameterTypes();          (Class clazzParam : clazzParams){             sBuilder.append(clazzParam.getName()).append();                       }          (clazzParams!= &&clazzParams.!=0)          sBuilder.deleteCharAt(sBuilder.length()-1);                              sBuilder.append();          System..println(sBuilder.toString());      }            Method[] methods=clazzProxy1.getMethods();          (Method method: methods){          String name=method.getName();          StringBuilder sBuilder= StringBuilder(name);          sBuilder.append();          Class[] clazzParams = method.getParameterTypes();          (Class clazzParam : clazzParams){             sBuilder.append(clazzParam.getName()).append();                       }          (clazzParams!= &&clazzParams.!=0)          sBuilder.deleteCharAt(sBuilder.length()-1);                              sBuilder.append();          System..println(sBuilder.toString());      }                System..println();          Constructor constructor = clazzProxy1.getConstructor(InvocationHandler.);                      MyInvocationHandler1InvocationHandler{                       

publicthrows

returnnull

new

out

//proxy1.size();                    ArrayList target= ArrayList(); 

new

"lideguo"

"zahgnsd"

"tsdfesd"

"nidenia"

out

out

   Object getProxy( Object target, Advice advice) {      Object proxy3=Proxy.newProxyInstance(             target.getClass().getClassLoader(),              target.getClass().getInterfaces(),             InvocationHandler(){ 

@Override                 Object invoke(Object proxy, Method method,                        Object[] args) Throwable {                                        advice.bfMethod(method);                    Object retVal=method.invoke(target, args);                    advice.afMethod(method);                                        retVal;                 }                              }             );      proxy3;   } 

 

56、实现类似spring的可配置的AOP框架

1】配置文件 config.properties

aop.ProxyFactoryBeancomeon.advice=

java.util.ArrayList

import

java.lang.reflect.*; 

publicclass

   Advice ;      Object ;      Advice getAdvice() {      ;   } 

publicvoid

thisadvice

   Object getTarget() {      ;   } 

publicvoid

thistarget

   Object getProxy() {      TODO

target

target

new

                 

public

throws

advice

target

advice

return

return

} 

java.io.IOException;import

java.util.Properties; 

BeanFactory { 

propsnew

publicthrows

props

publicthrows

props

ifinstanceof

null

try

forName(props".advice"

forName(props".target"

catch

//Auto-generated catch block             e.printStackTrace();          }          proxy;      }            bean;   }}import

java.util.Collection; 

AopFrameworkTest { 

/**    

*@throwsException

*/   main(String[] args)Exception {      TODO

      InputStream ips=AopFrameworkTest..getResourceAsStream();      Object  bean= BeanFactory(ips).getBean();      System..println(bean.getClass().getName());      ((Collection)bean).clear();   }