关于android 增量更新的实现

一般来说没有特殊要求的话  使用三方的SDK比如友盟的增量热更新就可以了  可以查看链接 

如果有需要自己实现的话 只能硬着头皮来了
实现方法：

增量更新的流程是：用户手机上安装着某个应用，下载了增量包，手机上的apk和增量包合并形成新的包，然后再次安装（注意这个过程是要重新安装的，当然部分应用市场有root权限你可能感知不到）。

ok，那么把整个流程细化为几个关键点：
用户手机上提取当前安装应用的apk
如何利用old.apk和new.apk生成增量文件
增加文件与1.中的old.apk合并，然后安装

解决了上述3个问题，就ok了。

下面开始解决，首先我们看下增量文件的生成与合并，这个环节可以说是整个流程的核心，也是技术难点，值得开心的是，这个技术难点已经有工具替我们实现了。

二、增量文件的生成与合并

这个其实就是利用工具做二进制的一个diff和patch了。

网址：
http://www.daemonology.net/bsdiff/

下载地址：
http://www.daemonology.net/bsdiff/bsdiff-4.3.tar.gz

对了，本文环境为mac，其他系统如果阻碍，慢慢搜索解决即可。

下载好了，解压，切到对应的目录，然后执行make：

<code class="hljs css has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">aaa</span><span class="hljs-pseudo" style="color: rgb(0, 0, 0); box-sizing: border-box;">:bsdiff-4</span><span class="hljs-class" style="box-sizing: border-box; color: rgb(155, 112, 63);">.3</span> <span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">zhy</span>$ <span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">make</span>
<span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">Makefile</span><span class="hljs-pseudo" style="color: rgb(0, 0, 0); box-sizing: border-box;">:13</span>: *** <span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">missing</span> <span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">separator</span>.  <span class="hljs-tag" style="color: rgb(0, 0, 0); box-sizing: border-box;">Stop</span>.</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

恩，你没看错，报错了，这个错误还比较好解决。

解压文件里面有个文件：Makefile，以文本的形式打开，将install：下面的if,endif添加一个缩进。

修改完成是这个样子的：

<code class="hljs lasso has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">CFLAGS      <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">+=</span>  <span class="hljs-attribute" style="box-sizing: border-box;">-O3</span> <span class="hljs-attribute" style="box-sizing: border-box;">-lbz2</span>

PREFIX      <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">?=</span>  /usr/<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">local</span>
INSTALL_PROGRAM <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">?=</span>  ${INSTALL} <span class="hljs-attribute" style="box-sizing: border-box;">-c</span> <span class="hljs-attribute" style="box-sizing: border-box;">-s</span> <span class="hljs-attribute" style="box-sizing: border-box;">-m</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">555</span>
INSTALL_MAN <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">?=</span>  ${INSTALL} <span class="hljs-attribute" style="box-sizing: border-box;">-c</span> <span class="hljs-attribute" style="box-sizing: border-box;">-m</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">444</span>

<span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">all</span>:        bsdiff bspatch
bsdiff:     bsdiff<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>c
bspatch:    bspatch<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>c

install:
${INSTALL_PROGRAM} bsdiff bspatch ${PREFIX}/bin
<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>ifndef WITHOUT_MAN
${INSTALL_MAN} bsdiff<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.1</span> bspatch<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">.1</span> ${PREFIX}/man/man1
<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>endif</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul>

然后，重新执行make:

<code class="hljs lasso has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">aaa:bsdiff<span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">-</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4.3</span> zhy$ make
cc <span class="hljs-attribute" style="box-sizing: border-box;">-O3</span> <span class="hljs-attribute" style="box-sizing: border-box;">-lbz2</span>    bsdiff<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>c   <span class="hljs-attribute" style="box-sizing: border-box;">-o</span> bsdiff
cc <span class="hljs-attribute" style="box-sizing: border-box;">-O3</span> <span class="hljs-attribute" style="box-sizing: border-box;">-lbz2</span>    bspatch<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>c   <span class="hljs-attribute" style="box-sizing: border-box;">-o</span> bspatch
bspatch<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>c:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">39</span>:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">21</span>: error: unknown <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">type</span> name <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'u_char'</span>; did you mean <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'char'</span><span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">?</span>
static off_t offtin(u_char <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">*</span>buf)
^~~~~~
char</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li></ul>

这次比上次好点，这次生成了一个bsdiff，不过在生成bspatch的时候报错了，好在其实我们只需要使用bsdiff，为什么这么说呢？

因为生成增量文件肯定是在服务端，或者是我们本地pc上做的，使用的就是bsdiff这个工具；

另外一个bspatch，合并old.apk和增量文件肯定是在我们应用内部做的。

当然这个问题也是可以解决的，搜索下，很多解决方案，我们这里就不继续在这个上面浪费篇幅了。

我这里提供个下载地址：

https://github.com/hymanAndroid/tools/tree/master/bsdiff-4.3

下载完成，直接make，bsdiff和bspatch都会生成（mac环境下）。

=============神奇的分割线==============

ok，假设到这里，不管你使用何种手段，咱们已经有了bsdiff和bspacth，下面演示下这个工具的使用：

首先我们准备两个apk，old.apk和new.apk，你可以自己随便写个项目，先运行一次拿到生成的apk作为old.apk；然后修改些代码，或者加一些功能，再运行一次生成new.apk；
生成增量文件

<code class="hljs oxygene has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">./bsdiff <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">old</span>.apk <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span>.apk <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">old</span>-<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">to</span>-<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span>.patch</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

这样就生成了一个增量文件old-to-new.patch
增量文件和old.apk合并成新的apk

<code class="hljs oxygene has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">./bspatch <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">old</span>.apk new2.apk <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">old</span>-<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">to</span>-<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span>.patch</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

这样就生成一个new2.apk

那么怎么证明这个生成的new2.apk和我们的new.apk一模一样呢？

我们可以查看下md5的值，如果两个文件md5值一致，那么几乎可以肯定两个文件时一模一样的（不要跟我较真说什么碰撞可以产生一样的md5的值~~）。

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-label" style="box-sizing: border-box;">aaa:</span>bsdiff-<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4.3</span> zhy$ md5 new<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apk</span>
MD5 (new<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apk</span>) = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0900</span>d0d65f49a0cc3b472e14da11bde7
<span class="hljs-label" style="box-sizing: border-box;">aaa:</span>bsdiff-<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4.3</span> zhy$ md5 new2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apk</span>
MD5 (new2<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apk</span>) = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0900</span>d0d65f49a0cc3b472e14da11bde7</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

可以看到两个文件的md5果然一样~~

恩，假设你不是mac，怎么获取一个文件的md5呢？（自己写代码，下载工具，不要遇到这样的问题，还弹窗我，我会被扣工资的…）

那么到这里我们就已经知道了如何生成增量文件和将patch与旧的文件合并为新的文件。那么我们再次梳理下整个流程：
服务端已经做好了增量文件（本节完成）
客户端下载增量文件+提取该应用的apk，使用bspatch合并
产生的新的apk，调用安装程序

还是蛮清晰的，那么主要是第二点，第二点有两件事，一个是提取应用的apk；一个是使用bspatch合并，那么这个合并肯定是需要native方法和so文件去做的，也就是说我们要自己打个so出来；

三、客户端的行为

（1）提取应用的apk文件

其实提取当前应用的apk非常简单，如下代码：

<code class="hljs cs has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> ApkExtract {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> String <span class="hljs-title" style="box-sizing: border-box;">extract</span>(Context context) {
context = context.getApplicationContext();
ApplicationInfo applicationInfo = context.getApplicationInfo();
String apkPath = applicationInfo.sourceDir;
Log.d(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"hongyang"</span>, apkPath);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> apkPath;
}
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li></ul>

(2)制作bspatch so

首先声明一个类，写个native方法，如下：

<code class="hljs cs has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> BsPatch {

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> {
System.loadLibrary(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"bsdiff"</span>);
}

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> native <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> <span class="hljs-title" style="box-sizing: border-box;">bspatch</span>(String oldApk, String newApk, String patch);

}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li></ul>

三个参数已经很明确了；

同时别忘了在module的build.gradle下面：

<code class="hljs matlab has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">defaultConfig <span class="hljs-cell" style="box-sizing: border-box;">{
ndk {
moduleName = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'bsdiff'</span>
}</span>
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

注意该步骤需要你配置过ndk的环境（下载ndk，设置ndk.dir）~

ok，接下来就是去完成c的代码的编写了；

首先在app/main目录下新建一个文件夹jni，把之前下载的bsdiff中的bspatch.c拷贝进去；

然后按照jni的规则，在里面新建一个方法：

<code class="hljs coffeescript has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">JNIEXPORT jint JNICALL Java_com_zhy_utils_BsPatch_bspatch
(JNIEnv *env, jclass cls,
jstring old, jstring <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span>, jstring patch){
int argc = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4</span>;
char * argv[argc];
argv[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>] = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"bspatch"</span>;
argv[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>] = <span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(char*)</span> <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">((*env)->GetStringUTFChars(env, old, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>))</span>;
<span class="hljs-title" style="box-sizing: border-box;">argv</span>[2] = <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(char*)</span> <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">((*env)->GetStringUTFChars(env, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span>, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>))</span>;
<span class="hljs-title" style="box-sizing: border-box;">argv</span>[3] = <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(char*)</span> <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">((*env)->GetStringUTFChars(env, patch, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>))</span>;

<span class="hljs-title" style="box-sizing: border-box;">int</span> <span class="hljs-title" style="box-sizing: border-box;">ret</span> = <span class="hljs-title" style="box-sizing: border-box;">patchMethod</span><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(argc, argv)</span>;

<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(*env)</span>-></span>ReleaseStringUTFChars(env, old, argv[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>]);
<span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(*env)</span>-></span>ReleaseStringUTFChars(env, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span>, argv[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>]);
<span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(*env)</span>-></span>ReleaseStringUTFChars(env, patch, argv[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3</span>]);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> ret;
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li></ul>

方法名是有规律的，这个规律不用提了吧~~

注意bsdiff.c中并没有patchMethod方法，这个方法实际上是main方法，直接修改为patchMethod即可，觉得复杂没关系，文末有源码。

ok，此时你可以尝试运行，会提示依赖bzlib，其实从文件顶部的include中也能看出来。

既然依赖，那我们就导入吧：

首先下载：
http://www.bzip.org/downloads.html
http://www.bzip.org/1.0.6/bzip2-1.0.6.tar.gz

下载完成后，解压：



将其中的.h和.c文件提取出来，然后可以选择连文件夹copy到我们module的app/main/jni下，结果如下：



记得修改bsdiff中的include：

<code class="hljs ruleslanguage has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-array" style="box-sizing: border-box;">#include </span><span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"bzip2/bzlib.h"</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

再次运行；

然后会发现报一堆类似下面的错误：

<code class="hljs asciidoc has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">Error:(70) multiple definition of <span class="hljs-smartquote" style="box-sizing: border-box;">`main'</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

提示main方法重复定义了，在出错信息中会给出哪些类中包含main方法，可以选择直接将这些类中的main方法直接删除。

删除以后，就ok了~~

那么到这里，我们就完成了JNI的编写，当然文件是bsdiff提供的c源码。

四、增量更新后安装

上面的操作完成后，最后一步就简单了，首先准备两个apk：

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">old<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apk</span> new<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.apk</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

然后制作一个patch，下面代码中的PATCH.patch；

将old.apk安装，然后将new.apk以及PATCH.patch放置到存储卡；

最后在Activity中触发调用：

<code class="hljs java has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">doBspatch</span>() {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> File destApk = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(Environment.getExternalStorageDirectory(), <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"dest.apk"</span>);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> File patch = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(Environment.getExternalStorageDirectory(), <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"PATCH.patch"</span>);

<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//一定要检查文件都存在</span>

BsPatch.bspatch(ApkExtract.extract(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>),
destApk.getAbsolutePath(),
patch.getAbsolutePath());

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (destApk.exists())
ApkExtract.install(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>, destApk.getAbsolutePath());
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li></ul>

记得开启读写SDCard权限，记得在代码中校验需要的文件都存在。

install实际就是通过Intent去安装了：

<code class="hljs cs has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">install</span>(Context context, String apkPath) {
Intent i = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Intent(Intent.ACTION_VIEW);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
i.setDataAndType(Uri.fromFile(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(apkPath)),
<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"application/vnd.android.package-archive"</span>);
context.startActivity(i);
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li></ul>

这里7.0可能会有问题，把路径暴露给别的app了，应该需要FileProvider去实现（未实验，猜测可能有可能）。

大致的效果图如下：

五、总结

如果你只是单纯的要使用该功能，大可以直接将生成的so文件拷入，直接loadLibrary使用即可。

其次，在做增量更新的时候，patch肯定是根据你当前的版本号与最新（或者目标）版本apk，比对下发diff文件，于此同时应该也把目标apk的md5下发，再做完合并后，不要忘记校验下md5；

博客结束，虽然很简单，主要利用工具实现，但是还是建议自己去实现一次，想一次性跑通还是需要一些时间的，可能过程中也会发现一些坑，也能提升自己对JNI的熟练度。

源码：
https://github.com/hongyangAndroid/BsDiff_And_Patch

也可以选择直接使用so
https://github.com/hongyangAndroid/BsDiff_And_Patch/tree/master/so-dist