如何读取从JAVA ANTLR输入的文件？ [关闭]

Question

关闭。这个问题需要更多focused。它当前不接受答案。

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是否要改善此问题？更新问题，使其仅按editing this post专注于一个问题。

[<5天前关闭。

我在使用Java Antlr读取文件时遇到问题。我从要使用文件读取器方法读取文件的字符串中读取数据]

   String code_input1 = 
                "import java.util.HashMap;\r\n" + 
                "import java.util.Map;\r\n" + 
                "\r\n" + 
                "public class UserService {\r\n" + 
                "    public static Map < String, String > cache = new HashMap < > (); // GLOBAL VARIABLE\r\n" + 
                "    public static final String GLOBAL_USER_NAME = \"RAMESH\"; // GLOBAL VARIABLE\r\n" + 
                "    public static final int ID = 100; // GLOBAL VARIABLE\r\n" + 
                "\r\n" + 
                "    public static Map < String, String > getCache() {\r\n" + 
                "        return cache;\r\n" + 
                "    }\r\n" + 
                "\r\n" + 
                "    // Put data in global cache variable\r\n" + 
                "    public static void putCache(String key, String value) {\r\n" + 
                "        cache.put(key, value);\r\n" + 
                "    }\r\n" + 
                "}";

Java9BaseListener listener1 = parse(code_input1);

Answer 1

您的代码应具有以下内容：

        import org.antlr.v4.runtime.tree.ParseTree;
        import org.antlr.v4.runtime.CodePointCharStream;
        import com.itsallbinary.grammer.java9.Java9Lexer;
        import org.antlr.v4.runtime.CommonTokenStream;
        import com.itsallbinary.grammer.java9.Java9Parser;


        ...
        // Prepare lexer & parser 
        CodePointCharStream inputStream = CharStreams.fromString(code_input1);
        Java9Lexer Java9Lexer = new Java9Lexer(inputStream);
        CommonTokenStream commonTokenStream = new CommonTokenStream(java9Lexer);
        Java9Parser java9Parser = new Java9Parser(commonTokenStream);

        // Prepare parse tree 
        ParseTree tree = java9Parser.compilationUnit();

Answer 2

也许CharStreams.fromFile("filename")？示例：

CharStream chars = CharStreams.fromFile("input.txt);
Lexer lexer = new SomeLexer(chars);

...