我使用 Java.g 中的语法ANTLRwiki 为 Java 源文件生成词法分析器和解析器。然后使用以下代码生成抽象语法树(AST).
ANTLRInputStream input = new ANTLRInputStream(new FileInputStream(fileName));
JavaLexer lexer = new JavaLexer(input); // create lexer
// create a buffer of tokens pulled from the lexer
CommonTokenStream tokens = new CommonTokenStream(lexer);
JavaParser parser = new JavaParser(tokens); // create parser
JavaParser.javaSource_return r = parser.javaSource(); // parse rule 'javaSource'
/*RuleReturnScope result = parser.compilationUnit();
CommonTree t = (CommonTree) result.getTree();*/
// WALK TREE
// get the tree from the return structure for rule prog
CommonTree t = (CommonTree)r.getTree();
然后修改AST。例如,替换“File file = new File(filepath, fileType);”到
“S3Object _file = new S3Object(_fileName);”通过修改 AST 节点。之后,我想将这个 AST 翻译为 java 源代码。我修改 JavaTreeParser.g 并编写一个字符串模板,并使用以下方法获取 java 源代码:
FileReader groupFileR = new FileReader("src/com/googlecode/zcg/templates/JavaTemplate.stg");
StringTemplateGroup templates = new StringTemplateGroup(groupFileR);
groupFileR.close();
// create a stream of tree nodes from AST built by parser
CommonTreeNodeStream nodes = new CommonTreeNodeStream(t);
// tell it where it can find the token objects
nodes.setTokenStream(tokens);
JavaTreeParser walker = new JavaTreeParser(nodes); // create the tree Walker
walker.setTemplateLib(templates); // where to find templates
// invoke rule prog, passing in information from parser
JavaTreeParser.javaSource_return r2 = walker.javaSource();
// EMIT BYTE CODES
// get template from return values struct
StringTemplate output = (StringTemplate)r2.getTemplate();
System.out.println(output.toString()); // render full template
如果我不修改 AST,它会正确获取 java 源代码,但是在我修改 AST 后,它不会获取正确的 java 源代码(AST 已正确修改)。例如,如果我输入如下源代码,并翻译为AST,然后修改“File file = new File(filepath, fileType);”到“S3Object _file = new S3Object(_fileName);”:
public void methodname(String address){
String filepath = "file";
int fileType = 3;
File file = new File(filepath, fileType);
}
结果如下:
public void methodname( String address)
{
String filepath="file";
int fileType=3;
methodname (Stringaddress){Stringfilepath;//it's not what I wanted
}
我做错了吗?有没有更合适的方法来解决我这个问题?