最近需要一些比较骚的操作，所以需要将gson编译成dex。

因为手上有jar包，所以就拿出了android sdk准备一把入魂，结果报错不断，让人无奈。只好根据报错来调整编译步骤，不得不为安卓环境更新Debug。

1、dx变d8

并不确定安卓更名的原因，但找到这个只是根据名字前面有个相同的d，这对于不太熟悉更新的人来说，只能靠蒙。

并不确定从哪个版本开始，dx.bat更新成了d8.bat。而且在使用中，命令方式也发生了变化，这个后面再讲。

所以，原来的dx --dex --output xxx.dex xxx.jar命令，不能使用了。

2、jre环境报错。

日常使用java的人，我觉得大多数人还是使用1.8。

不过随着各种软件，及编译环境的更新，java1.8的问题慢慢出现了，也出现了各种不兼容的情况。

只是到目前为止，还没有更新的动力。

这次编译，报错了：

Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError: com/android/tools/r8/D8 has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0at java.lang.ClassLoader.defineClass1(Native Method)at java.lang.ClassLoader.defineClass(Unknown Source)at java.security.SecureClassLoader.defineClass(Unknown Source)at java.net.URLClassLoader.defineClass(Unknown Source)at java.net.URLClassLoader.access$100(Unknown Source)at java.net.URLClassLoader$1.run(Unknown Source)at java.net.URLClassLoader$1.run(Unknown Source)at java.security.AccessController.doPrivileged(Native Method)at java.net.URLClassLoader.findClass(Unknown Source)at java.lang.ClassLoader.loadClass(Unknown Source)at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)at java.lang.ClassLoader.loadClass(Unknown Source)at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

报错就是说java1.8太老了，带不动了。

所以，切换java版本，运行了，继续报错。

3、命令换了

C:\Users\Administrator\Desktop\gson>d8
Exception in thread "main" java.lang.RuntimeException: Invalid invocation.
Usage: d8 [options] [@<argfile>] <input-files>where <input-files> are any combination of dex, class, zip, jar, or apk filesand each <argfile> is a file containing additional arguments (one per line)and options are:--debug                 # Compile with debugging information (default).--release               # Compile without debugging information.--output <file>         # Output result in <file>.# <file> must be an existing directory or a zip file.--lib <file|jdk-home>   # Add <file|jdk-home> as a library resource.--classpath <file>      # Add <file> as a classpath resource.--min-api <number>      # Minimum Android API level compatibility (default: 1).--pg-map <file>         # Use <file> as a mapping file for distribution.--intermediate          # Compile an intermediate result intended for later# merging.--file-per-class        # Produce a separate dex file per class.# Synthetic classes are in their own file.--file-per-class-file   # Produce a separate dex file per input .class file.# Synthetic classes are with their originating class.--no-desugaring         # Force disable desugaring.--desugared-lib <file>  # Specify desugared library configuration.# <file> is a desugared library configuration (json).--desugared-lib-pg-conf-output <file># Output the Proguard configuration for L8 to <file>.--main-dex-rules <file> # Proguard keep rules for classes to place in the# primary dex file.--main-dex-list <file>  # List of classes to place in the primary dex file.--main-dex-list-output <file># Output resulting main dex list in <file>.--force-enable-assertions[:[<class name>|<package name>...]]--force-ea[:[<class name>|<package name>...]]# Forcefully enable javac generated assertion code.--force-disable-assertions[:[<class name>|<package name>...]]--force-da[:[<class name>|<package name>...]]# Forcefully disable javac generated assertion code.# This is the default handling of javac assertion code# when generating DEX file format.--force-passthrough-assertions[:[<class name>|<package name>...]]--force-pa[:[<class name>|<package name>...]]# Don't change javac generated assertion code. This# is the default handling of javac assertion code when# generating class file format.--force-assertions-handler:<handler method>[:[<class name>|<package name>...]]--force-ah:<handler method>[:[<class name>|<package name>...]]# Change javac and kotlinc generated assertion code# to invoke the method <handler method> with each# assertion error instead of throwing it.# The <handler method> is specified as a class name# followed by a dot and the method name.# The handler method must take a single argument of# type java.lang.Throwable and have return type void.--thread-count <number> # Use <number> of threads for compilation.# If not specified the number will be based on# heuristics taking the number of cores into account.--map-diagnostics[:<type>] <from-level> <to-level># Map diagnostics of <type> (default any) reported as# <from-level> to <to-level> where <from-level> and# <to-level> are one of 'info', 'warning', or 'error'# and the optional <type> is either the simple or# fully qualified Java type name of a diagnostic.# If <type> is unspecified, all diagnostics at# <from-level> will be mapped.# Note that fatal compiler errors cannot be mapped.--android-platform-build# Compile as a platform build where the runtime/bootclasspath# is assumed to be the version specified by --min-api.--art-profile <input> <output># Rewrite human readable ART profile read from <input> and write to <output>.--startup-profile <file># Startup profile <file> to use for dex layout.--version               # Print the version of d8.--help                  # Print this message.

最显著的变化有两个：

1、不再需要 --dex 命令

2、不能直接转化成.dex文件，需要zip或者jar后缀。