Java 编译器树 API : NPE

Question

我正在尝试使用另一个 treepathscanner 访问方法主体，但我不知道要传递哪个参数，因为我总是在 TreePath 构造函数中得到一个 NPE。

@Override
public Object visitMethod(MethodTree node, Trees p) {
    ...
    node.getBody().accept(new MethodVisitor(m, repository), node.getBody());
    ...
}


public class MethodVisitor extends TreePathScanner<Object, BlockTree> {...}

异常(exception):

An annotation processor threw an uncaught exception.
Consult the following stack trace for details.
java.lang.NullPointerException
    at com.sun.source.util.TreePath.<init>(TreePath.java:94)
    at com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:65)
    at com.sun.source.util.TreeScanner.scan(TreeScanner.java:90)
    at com.sun.source.util.TreeScanner.visitBlock(TreeScanner.java:158)
    at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:764)
    at cz.cvut.kbss.odpa.parser.visitor.OdpaVisitor.visitMethod(OdpaVisitor.java:93)
    at cz.cvut.kbss.odpa.parser.visitor.OdpaVisitor.visitMethod(OdpaVisitor.java:29)
    at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:676)
    at com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:67)
    ...

感谢您的帮助。

Answer 1

如果有人需要它，正确的调用方式是:

new MethodVisitor(m, repository).scan(p.getPath(compilationUnitTree, node), node.getBody());