搭建ndk+cmake环境
setting中system settings->android sdk->sdk tools，把如下三条勾选上，apply自动下载

环境搭建

先下载bsdiff和bspatch文件以及bzip2包https://pan.baidu.com/s/1boTzvsj 全部打包在了一起

在src/main目录下，新建cpp文件夹，将上面压缩包，解压后复制进去

在cpp目录下，新建一个c文件patch.c

包结构

#include <jni.h>

#include "bzip2/bsdiff.c"
#include "bzip2/bspatch.c"

JNIEXPORT jint JNICALL
Java_com_nick_bsdiff_Diffutils_generateDiffApk(JNIEnv *env, jclass type, jstring oldPath_,
                                               jstring newPath_, jstring patchPath_) {
    int argc = 4;
    char *argv[argc];
    argv[0] = (char *) "bspatch";
    argv[1] = (char *) (*env)->GetStringUTFChars(env, oldPath_, 0);
    argv[2] = (char *) (*env)->GetStringUTFChars(env, newPath_, 0);
    argv[3] = (char *) (*env)->GetStringUTFChars(env, patchPath_, 0);

    jint result = generateDiffApk(argc, argv);

    (*env)->ReleaseStringUTFChars(env, oldPath_, argv[1]);
    (*env)->ReleaseStringUTFChars(env, newPath_, argv[2]);
    (*env)->ReleaseStringUTFChars(env, patchPath_, argv[3]);
    return result;
}

JNIEXPORT jint JNICALL
Java_com_nick_bsdiff_Diffutils_mergeDiffApk(JNIEnv *env, jclass type, jstring oldPath_,
                                            jstring newPath_, jstring patchPath_) {

    int argc = 4;
    char *argv[argc];
    argv[0] = (char *) "bspatch";
    argv[1] = (char *) (*env)->GetStringUTFChars(env, oldPath_, 0);
    argv[2] = (char *) (*env)->GetStringUTFChars(env, newPath_, 0);
    argv[3] = (char *) (*env)->GetStringUTFChars(env, patchPath_, 0);

    printf("old apk = %s \n", argv[1]);
    printf("patch = %s \n", argv[3]);
    printf("new apk = %s \n", argv[2]);

    jint result = mergeDiffApk(argc, argv);

    (*env)->ReleaseStringUTFChars(env, oldPath_, argv[1]);
    (*env)->ReleaseStringUTFChars(env, newPath_, argv[2]);
    (*env)->ReleaseStringUTFChars(env, patchPath_, argv[3]);
    return result;
}

java文件中，新建DiffUtil.java

package com.nick.bsdiff;

/**
 * Created by nick on 2017/2/27.
 */

public class Diffutils {

    static {
        System.loadLibrary("patch");
    }


    /**
     * @param oldPath 旧的安装包路径
     * @param newPath 新的安装包路径
     * @param patchPath 差分包路径
     * @return 生成的结果
     */
    public static native int generateDiffApk(String oldPath, String newPath, String patchPath);

    /**
     * @param oldPath 旧的安装包路径
     * @param newPath 新的安装包路径
     * @param patchPath 差分包路径
     * @return 生成的结果
     */
    public static native int mergeDiffApk(String oldPath, String newPath, String patchPath);
}

注意c文件中的方法名为java文件的包名+方法名

在项目最外层目录，新建CMakeLists.txt

# Sets the minimum version of CMake required to build the native
# library. You should either keep the default value or only pass a
# value of 3.4.0 or lower.

cmake_minimum_required(VERSION 3.4.1)

# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds it for you.
# Gradle automatically packages shared libraries with your APK.

add_library( # Sets the name of the library.
             patch

             # Sets the library as a shared library.
             SHARED

             # Provides a relative path to your source file(s).
             # Associated headers in the same location as their source
             # file are automatically included.
             src/main/cpp/patch.c )

#最后的斜杠一定要加
include_directories(src/main/cpp/bzip2/)

# Searches for a specified prebuilt library and stores the path as a
# variable. Because system libraries are included in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.

find_library( # Sets the name of the path variable.
              log-lib

              # Specifies the name of the NDK library that
              # you want CMake to locate.
              log )

# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in the
# build script, prebuilt third-party libraries, or system libraries.

target_link_libraries( # Specifies the target library.
                       patch

                       # Links the target library to the log library
                       # included in the NDK.
                       ${log-lib} )

module的gradle中，android{}方法中，添加

externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }

Project的gradle.properties中添加
android.useDeprecatedNdk=true

手动生成patch的方法：
下载两个exe文件，bsdiff拆分 bspatch合并
https://pan.baidu.com/s/1pLGzWBx

使用 cmd切换到目录下 执行
bsdiff old.apk new.apk old-to-new.patch
生成增量文件 old为老包 new 为新包 patch为生成的patch 在同一路径下 若不同路径 需写完整路径

bspatch old.apk new2.apk old-to-new.patch
合并包