Proguard是个优秀的java混淆工具，使用示例如下，一个java工程对外接口代码如下（无需混淆）

package com.ciaos.open;import com.ciaos.inner.InnerTool;public class OpenTool {    public static void method()    {        System.out.println("public method");        InnerTool.method();    }}

内部调用函数如下（需要混淆）

package com.ciaos.inner;public class InnerTool {    public static void method()    {        System.out.println("need encrypt");    }}

我们只想在打包的jar文件中保留OpenTool.method接口，则proguard配置文件library.pro文件如下：

## This ProGuard configuration file illustrates how to process a program# library, such that it remains usable as a library.# Usage:#     java -jar proguard.jar @library.pro## Specify the input jars, output jars, and library jars.# In this case, the input jar is the program library that we want to process.-injars  D:\libtool.jar-outjars D:\libtool_min.jar-libraryjars  C:\Users\shipeng\AppData\Local\MyEclipse Professional 2014\binary\com.sun.java.jdk7.win32.x86_1.7.0.u45\jre\lib\rt.jar#-libraryjars  E:\Works\fastjson-1.1.34.android.jar-printmapping map\proguard.map -overloadaggressively -defaultpackage ''  -allowaccessmodification -dontoptimize-overloadaggressively-keepattributes InnerClasses,SourceFile,LineNumberTable,Signature-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*-optimizationpasses 5-keepattributes Exceptions-keep public class com.ciaos.open.OpenTool{   public *; }#-keep public class com.ciaos.inner.InnerTool #{   #public *; #}

混淆工具脚本

del "D:\libtool_min.jar"java -jar lib/proguard.jar @library.propause

更多用法参照，proguard也有插件集成到eclipse中。