如何使用ANTLRInputStream從文件讀取輸入？

Question

我在web 中嘗試了很多例子，但找不到任何工作示例。如何使用ANTLRInputStream

所以文件 讀取輸入，我可以很容易地理解

所以，請提供一個工作的例子。

在此先感謝。

Answer 1

實際上，將標準FileInputStream傳遞給ANTLRInputStream並不複雜。

從可以看出，ANTLRInputStrean是什麼它將接受相當寬鬆的文件，所以如果你有傳遞一個字符串或字符[]數組，那麼我懷疑有麻煩的是更大的問題：

ANTLRInputStream() 
ANTLRInputStream(char[] data, int numberOfActualCharsInArray) 
This is the preferred constructor for strings as no data is copied 
ANTLRInputStream(InputStream input) 
ANTLRInputStream(InputStream input, int initialSize) 
ANTLRInputStream(InputStream input, int initialSize, int readChunkSize) 
ANTLRInputStream(Reader r) 
ANTLRInputStream(Reader r, int initialSize) 
ANTLRInputStream(Reader r, int initialSize, int readChunkSize) 
ANTLRInputStream(String input) 
Copy data in string to a local char array 

你問例如所以這裏是例子：

import java.io.File; 
import java.io.FileInputStream; 
import java.io.IOException; 

import org.antlr.v4.runtime.ANTLRInputStream; 
import org.antlr.v4.runtime.CommonTokenStream; 
import org.antlr.v4.runtime.tree.ParseTree; 
import org.antlr.v4.runtime.tree.ParseTreeWalker; 

// You're going to need to implement these based on the grammar you've created 
import your.package.here.MyLangListener; 
import your.package.here.MyLangTranslator; 

// These are generated by ANTLR 
import your.package.here.parser.LangLexer; 
import your.package.here.LangParser; 


public class App { 
    public static void main(String[] args) { 
     String fileName = "someInputBasedOnYourGrammarRules.lang"; 
     File file = new File(fileName); 
     FileInputStream fis = null; 

     try { 
      // Open the input file stream 
      fis = new FileInputStream(file); 

      // Create a CharStream that reads from standard input 
      ANTLRInputStream input = new ANTLRInputStream(fis); 

      // Create a lexer that feeds off of input CharStream 
      LangLexer lexer = new LangLexer(input); 

      // Create a buffer of tokens pulled from the lexer 
      CommonTokenStream tokens = new CommonTokenStream(lexer); 

      // Create a parser that feeds off the tokens buffer 
      LangParser parser = new LangParser(tokens); 

      // Begin parsing at rule prog 
      ParseTree tree = parser.prog(); 

      // Close the input file 
      fis.close(); 

      // Create a generic parse tree walker that can trigger callbacks 
      ParseTreeWalker walker = new ParseTreeWalker(); 
      // Walk the tree created during the parse, trigger callbacks 
      walker.walk(new MyLangListener(), tree); 
      System.out.println(); // print a \n after translation 

      // Walk the tree again to translate to java 
      walker.walk(new MyLangTranslator(), tree); 

      // Print LISP-style tree 
      //System.out.println(tree.toStringTree(parser)); 
     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
    } 
} 

另外，我建議你使用ANTLR Maven插件。