Android热修复笔记
java--->class---jar--->dex
使用方法：1、运行修复的程序，
2、在build-->intermediates-->javac-->debug--->classes 在这个文件夹打开终端窗口运行 jar cvf fix.jar qzone/Fix.class
（javac -encoding UTF-8 qzone/Fix.java
或者
studio编译之后在build-intermediates-javac-debug-classes文件中查找）
3、得到jar之后，把classes的jar复制到sdk->build-tools->版本 中（dx）
使用 dx --dex --output=fix.dex fix.jar 命令 得到dex
image.png
image.png
image.png
image.png
FixUtil工具类
public class FixUtil {
static String TAG="hotfix";
public static void installPatch(Context context, String patchPath) {
PsyP();
File patchFile = new File(patchPath);
if (!patchFile.exists()) {
Log.e(TAG, "installPatch: " + patchPath + "无文件，无需修复");
return;
}
File optDir = context.getCacheDir();
try {
// 1.得到当前程序的classLoader
ClassLoader classLoader = context.getClassLoader();
// 2.反射获取类加载器的pathList属性
Field pathListField = getField(Class.forName("dalvik.system.BaseDexClassLoader"), "pathList");
Object pathList = pathListField.get(classLoader);
// 3.反射获取DexPathList中的dexElements
Field dexElementsField = getField(pathList.getClass(), "dexElements");
Object[] dexElements = (Object[]) dexElementsField.get(pathList);
// 4.加载自己的dex,并转化为Element[]
// 通过反射DexPathList 中的makeDexElements() 方法来实现
// 4.1 反射获取makeDexElements方法
Object[] patchElements = null;
// 版本适配
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
// Android 7.0+ 使用makeDexElements(List,File,List,ClassLoader)
Method makeDexElementsMethod = getMethod(pathList.getClass(), "makeDexElements", List.class, File.class, List.class, ClassLoader.class);
List<File> dexFileList = new ArrayList<>();
dexFileList.add(patchFile);
ArrayList<IOException> suppressedExceptions = new ArrayList<IOException>();
patchElements = (Object[]) makeDexElementsMethod.invoke(null, dexFileList, optDir, suppressedExceptions, classLoader);
} else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
// Android 6.0-7.0 使用makePathElements(List,File,List)
Method makePathElements = getMethod(pathList.getClass(), "makePathElements", List.class, File.class, List.class);
List<File> dexFileList = new ArrayList<>();
dexFileList.add(patchFile);
ArrayList<IOException> suppressedExceptions = new ArrayList<IOException>();
patchElements = (Object[]) makePathElements.invoke(null, dexFileList, optDir, suppressedExceptions);
} else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
// Android 5.0-6.0 使用makeDexElements(ArrayList,File,ArrayList) 注意这里参数编程ArrayList类型
Method makeDexElementsMethod = getMethod(pathList.getClass(), "makeDexElements", ArrayList.class, File.class, ArrayList.class);
List<File> dexFileList = new ArrayList<>();
dexFileList.add(patchFile);
ArrayList<IOException> suppressedExceptions = new ArrayList<IOException>();
patchElements = (Object[]) makeDexElementsMethod.invoke(null, dexFileList, optDir, suppressedExceptions);
} else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
// Android 4.4-5.0 使用makeDexElements(ArrayList,File,ArrayList) 注意这里参数编程ArrayList类型
// 和5.0一样的方法，注意4.4 会报错 Class ref in pre-verified class resolved to unexpected implementation
Log.e(TAG, "installPatch: 当前版本：" + Build.VERSION.SDK_INT + "此版本暂未解决 Class ref in pre-verified class resolved to unexpected implementation 的问题");
return;
} else {
Log.e(TAG, "installPatch: 当前版本：" + Build.VERSION.SDK_INT + "不支持热更新");
return;
}
// 5.合并两个Element[] patchElements要放在前面
Object[] newElements = (Object[]) Array.newInstance(dexElements.getClass().getComponentType(), dexElements.length + patchElements.length);
System.arraycopy(patchElements, 0, newElements, 0, patchElements.length);
System.arraycopy(dexElements, 0, newElements, patchElements.length, dexElements.length);
// 6.反射替换原来的dexElements
dexElementsField.set(pathList, newElements);
Log.e(TAG, "installPatch: 修复成功");
} catch (Exception e) {
e.printStackTrace();
Log.e(TAG, "installPatch: 修复失败!!" + e.getMessage());
}
}
/**
* 10.0以上反射调用隐蔽方法
*/
static void PsyP() {
if (SDK_INT < Build.VERSION_CODES.P) {
return;
}
try {
//设置豁免所有hide api https://developer.android.google.cn/about/versions/10/non-sdk-q
Method forName = Class.class.getDeclaredMethod("forName", String.class);
Method getDeclaredMethod = Class.class.getDeclaredMethod("getDeclaredMethod", String.class, Class[].class);
Class<?> vmRuntimeClass = (Class<?>) forName.invoke(null, "dalvik.system.VMRuntime");
Method getRuntime = (Method) getDeclaredMethod.invoke(vmRuntimeClass, "getRuntime", null);
Method setHiddenApiExemptions = (Method) getDeclaredMethod.invoke(vmRuntimeClass, "setHiddenApiExemptions", new Class[]{String[].class});
Object sVmRuntime = getRuntime.invoke(null);
setHiddenApiExemptions.invoke(sVmRuntime, new Object[]{new String[]{"L"}});
} catch (
Throwable e) {
Log.e("[error]", "reflect bootstrap failed:", e);
}
}
/**
* 反射获取属性 会从所有父类中找，不区分private
*/
public static Field getField(Class cls, String fieldName) {
// 如果自己类中找不到 就去父类中递归查找
Field declaredField = null;
while (cls != null) {
Log.e(TAG, "getField: 当前类" + cls.getName());
try {
declaredField = cls.getDeclaredField(fieldName);
if (declaredField != null) {
declaredField.setAccessible(true);
return declaredField;
}
} catch (NoSuchFieldException e) {
e.printStackTrace();
}
cls = cls.getSuperclass();
}
// 没有找到
return null;
}
/**
* 反射获取方法 会从所有父类中找，不区分private 注意方法需要传入参数
*/
public static Method getMethod(Class cls, String methodName, Class<?>... paramTypes) {
// 如果自己类中找不到 就去父类中递归查找
Method declaredMethod = null;
while (cls != null) {
try {
declaredMethod = cls.getDeclaredMethod(methodName, paramTypes);
if (declaredMethod != null) {
declaredMethod.setAccessible(true);
return declaredMethod;
}
cls = cls.getSuperclass();
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
}
// 没有找到
return null;
}
}
Fix修复类(要修复的类)
public class Fix {
public static String getMessage() {
// return "程序出bug了，赶紧叫人来修补！！！";
return "程序的问题已经修复完成(这是修复之后的类文件及方法)";
}
}
AppLication
public class App extends Application {
@Override
public void onCreate() {
super.onCreate();
Log.e("Application", "----------path:" + Environment.getExternalStorageDirectory().getAbsolutePath() + "/fix.dex");
FixUtil.installPatch(this, Environment.getExternalStorageDirectory().getAbsolutePath() + "/fix.dex");
// FixUtil.installPatch(this, getFilesDir()+ File.separator+"patch.dex");
}
}
