我是Java编程语言的初学者。我想从java源代码中提取AST并将AST打印到文件或标准输出。
我按照本教程学习如何使用AST。 http://www.programcreek.com/2011/01/a-complete-standalone-example-of-astparser/
所以根据我到目前为止的代码如下。
import java.util.HashSet;
import java.util.Set;
import org.eclipse.jdt.core.dom.AST;
import org.eclipse.jdt.core.dom.ASTParser;
import org.eclipse.jdt.core.dom.ASTVisitor;
import org.eclipse.jdt.core.dom.CompilationUnit;
import org.eclipse.jdt.core.dom.SimpleName;
import org.eclipse.jdt.core.dom.VariableDeclarationFragment;
public class Test {
public static void main(String args[]){
ASTParser parser = ASTParser.newParser(AST.JLS3);
parser.setSource("public class A { int i = 9; \n int j; \n ArrayList<Integer> al = new ArrayList<Integer>();j=1000; }".toCharArray());
//parser.setSource("/*abc*/".toCharArray());
parser.setKind(ASTParser.K_COMPILATION_UNIT);
//ASTNode node = parser.createAST(null);
final CompilationUnit cu = (CompilationUnit) parser.createAST(null);
}
}
我尝试使用以下代码段将其打印到标准输出,但它没有给出我预期的结果,
System.out.println(cu.getAST().toString());
如果有人可以帮我将AST打印到文件中,那将是一个很大的帮助。
提前致谢。
答案 0 :(得分:3)
这是an example of transforming the AST to JSON。您可以修改JSONStyleASTPrinter.java
文件以生成XML而不是JSON等。
基于How To Train the JDT Dragon combined.pdf的示例:
private void print(ASTNode node) {
List properties = node.structuralPropertiesForType();
for (Iterator iterator = properties.iterator(); iterator.hasNext();) {
Object descriptor = iterator.next();
if (descriptor instanceof SimplePropertyDescriptor) {
SimplePropertyDescriptor simple = (SimplePropertyDescriptor) descriptor;
Object value = node.getStructuralProperty(simple);
System.out.println(simple.getId() + " (" + value.toString() + ")");
} else if (descriptor instanceof ChildPropertyDescriptor) {
ChildPropertyDescriptor child = (ChildPropertyDescriptor) descriptor;
ASTNode childNode = (ASTNode) node.getStructuralProperty(child);
if (childNode != null) {
System.out.println("Child (" + child.getId() + ") {");
print(childNode);
System.out.println("}");
}
} else {
ChildListPropertyDescriptor list = (ChildListPropertyDescriptor) descriptor;
System.out.println("List (" + list.getId() + "){");
print((List) node.getStructuralProperty(list));
System.out.println("}");
}
}
}
private void print(List nodes) {
for (Iterator iterator = nodes.iterator(); iterator.hasNext();) {
print((ASTNode) iterator.next());
}
}