Java : parse java source code, extract methods

Question

I wish to parse java source code files, and extract the methods source code.

I would need a method like this :

/** Returns a map with key = method name ; value = method source code */ Map<String,String> getMethods(File javaFile); 

Is there a simple way to achieve this, a library to help me build my method, etc. ?

Answer 1

Download the java parser from https://javaparser.org/

You'll have to write some code. This code will invoke the parser... it will return you a CompilationUnit:

            InputStream in = null;             CompilationUnit cu = null;             try             {                     in = new SEDInputStream(filename);                     cu = JavaParser.parse(in);             }             catch(ParseException x)             {                  // handle parse exceptions here.             }             finally             {                   in.close();             }             return cu; 

Note: SEDInputStream is a subclass of input stream. You can use a FileInputStream if you want.

---

You'll have to create a visitor. Your visitor will be easy because you're only interested in methods:

  public class MethodVisitor extends VoidVisitorAdapter   {         public void visit(MethodDeclaration n, Object arg)         {              // extract method information here.              // put in to hashmap         }   } 

---

To invoke the visitor, do this:

  MethodVisitor visitor = new MethodVisitor();   visitor.visit(cu, null);