最通俗易懂的字节码插桩实战（Gradle + ASM）

input.jarInputs.each { JarInput jarInput ->

handleJarInput(jarInput, outputProvider)

}

}

}

/**

• 处理文件目录下的class文件

*/

static void handleDirectoryInput(DirectoryInput directoryInput, TransformOutputProvider outputProvider) {

//是否是目录

if (directoryInput.file.isDirectory()) {

//列出目录所有文件（包含子文件夹，子文件夹内文件）

directoryInput.file.eachFileRecurse { File file ->

def name = file.name

if (filterClass(name)) {

ClassReader classReader = new ClassReader(file.bytes)

ClassWriter classWriter = new ClassWriter(classReader, ClassWriter.COMPUTE_MAXS)

ClassVisitor classVisitor = new BuryPointVisitor(classWriter)

classReader.accept(classVisitor, ClassReader.EXPAND_FRAMES)

byte[] code = classWriter.toByteArray()

FileOutputStream fos = new FileOutputStream(file.parentFile.absolutePath + File.separator + name)

fos.write(code)

fos.close()

}

}

}

//文件夹里面包含的是我们手写的类以及R.class、BuildConfig.class以及R$XXX.class等

// 获取output目录

def dest = outputProvider.getContentLocation(

directoryInput.name,

directoryInput.contentTypes,

directoryInput.scopes,

Format.DIRECTORY)

//这里执行字节码的注入，不操作字节码的话也要将输入路径拷贝到输出路径

FileUtils.copyDirectory(directoryInput.file, dest)

}

/**

• 处理jar文件，一般是第三方依赖库jar文件

*/

static void handleJarInput(JarInput jarInput, TransformOutputProvider outputProvider) {

if (jarInput.file.getAbsolutePath().endsWith(“.jar”)) {

//重名名输出文件,因为可能同名,会覆盖

def jarName = jarInput.name

def md5Name = DigestUtils.md5Hex(jarInput.file.getAbsolutePath())

if (jarName.endsWith(“.jar”)) {

jarName = jarName.substring(0, jarName.length() - 4)

}

JarFile jarFile = new JarFile(jarInput.file)

Enumeration enumeration = jarFile.entries()

File tmpFile = new File(jarInput.file.getParent() + File.separator + “temp.jar”)

//避免上次的缓存被重复插入

if (tmpFile.exists()) {

tmpFile.delete()

}

JarOutputStream jarOutputStream = new JarOutputStream(new FileOutputStream(tmpFile))

//用于保存

while (enumeration.hasMoreElements()) {

JarEntry jarEntry = (JarEntry) enumeration.nextElement()

String entryName = jarEntry.getName()

ZipEntry zipEntry = new ZipEntry(entryName)

InputStream inputStream = jarFile.getInputStream(jarEntry)

//插桩class

if (filterClass(entryName)) {

//class文件处理

jarOutputStream.putNextEntry(zipEntry)

ClassReader classReader = new ClassReader(IOUtils.toByteArray(inputStream))

ClassWriter classWriter = new ClassWriter(classReader, ClassWriter.COMPUTE_MA