Android問題集錦之四十九：Can't add XStream file dependency to Android Studio project

將xstream1.4.8 引入Android Strudio項目中，編譯報錯如下：

UNEXPECTED TOP-LEVEL EXCEPTION:
com.android.dx.cf.iface.ParseException: bad class file magic (cafebabe) or version (0034.0000)
    at com.android.dx.cf.direct.DirectClassFile.parse0(DirectClassFile.java:472)
    at com.android.dx.cf.direct.DirectClassFile.parse(DirectClassFile.java:406)
    at com.android.dx.cf.direct.DirectClassFile.parseToInterfacesIfNecessary(DirectClassFile.java:388)
    at com.android.dx.cf.direct.DirectClassFile.getMagic(DirectClassFile.java:251)
    at com.android.dx.command.dexer.Main.processClass(Main.java:665)
    at com.android.dx.command.dexer.Main.processFileBytes(Main.java:634)
    at com.android.dx.command.dexer.Main.access$600(Main.java:78)
    at com.android.dx.command.dexer.Main$1.processFileBytes(Main.java:572)
    at com.android.dx.cf.direct.ClassPathOpener.processArchive(ClassPathOpener.java:284)
    at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:166)
    at com.android.dx.cf.direct.ClassPathOpener.process(ClassPathOpener.java:144)
    at com.android.dx.command.dexer.Main.processOne(Main.java:596)
    at com.android.dx.command.dexer.Main.processAllFiles(Main.java:498)
    at com.android.dx.command.dexer.Main.runMonoDex(Main.java:264)
    at com.android.dx.command.dexer.Main.run(Main.java:230)
    at com.android.dx.command.dexer.Main.main(Main.java:199)
    at com.android.dx.command.Main.main(Main.java:103)
...while parsing com/thoughtworks/xstream/mapper/LambdaMapper.class
1 error; aborting
Error:Execution failed for task ':app:preDexDebug'.
> com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command '/opt/jdk/jdk1.7.0_71/bin/java'' finished with non-zero exit value 1
Information:BUILD FAILED

究其原因，xstream1.4.8為Java8編譯，而目前AS尚只支持Java7。那麼我們只好使用低版本的xstream。

既然可以解析json和xml，那麼這個庫應該能夠吃得開才對。目前很多項目既要解析xml，又要解析json。如果一個庫搞定，學習成本會下降很多。