java 编译失败，其中带有 jar 文件的类路径

Question

There is a jar named 353.jar in a directory. I new a java class and import a class that is in 353.jar .

import com.coxier.test.DrawaerLayout;


class Test {
    public static void main(String[] args) {
        DrawaerLayout d = new DrawaerLayout();
    }
}

I compile Test.java with below command:

javac -verbose -classpath /Users/coxier/test/app/build/intermediates/transforms/dexBuilder/debug/353.jar:. TestA.java

But here is a error:

error: package com.coxier.test does not exist

EDIT 1

Thanks @Marquis. I know this jar is a dex format file.

jar tvf 351.jar

The output is: 1080024 Thu Jul 02 17:52:10 CST 2020 classes.dex

Answer 1

javac has nothing to do with android.

Android development can be done using a language that is extremely java like but not quite java. In particular, all the infrastructure around it, such as what the compiled code looks like, is entirely non-java (as in, the tooling that ships with not-android-targeted java, such as your OpenJDK installation, doesn't know about it and can't read any of it).

That jar file contains, as far as java itself is concerned (and javac is just java, not android), absolutely nothing: It has no idea what a dex file is, so that is just ignored.

This code would work if the jar file contained the entry:

/com/coxier/test/DrawaerLayout/Test.class

then, javac -cp thatJar.jar TestA.java would work, assuming TestA.java is in the current working directory and contains:

import com.coxier.test.DrawaerLayout.Test;

public class TestA {
    Test test;
}

If you have the source of that Test.dex file, you could make a class file instead, but it sounds like what you need is for TestA.java to also be compiled with the android toolkit, which presumably does know what dex files are, and may even accept them in jars (though I recall that jars aren't a thing android does either, just like it doesn't 'do' class files).