java - 我无法编译 antler_test.java

Question

` import org.anltr.v4.runtime.*;
import org.anltr.v4.runtime.tree.*;

public class antlr_test{
  public static void main(String[] args)throws Exception{
   ANTLRInputStream input = new ANTLRInputStream(System.in);
    exprLexer lexer = new exprLexer(input);
    CommonTokenStream tokens = new CommonTokenStream(lexer);
     exprParser parser = new exprParser(tokens);
    parser.prog();
  }
}`

`error: package org.anltr.v4.runtime does not exist
import org.anltr.v4.runtime.*;
^
antlr_test.java:3: error: package org.anltr.v4.runtime.tree does not exist
import org.anltr.v4.runtime.tree.*;
^
antlr_test.java:7: error: cannot find symbol
ANTLRInputStream input = new ANTLRInputStream(System.in);
^
symbol:   class ANTLRInputStream
location: class antlr_test
antlr_test.java:7: error: cannot find symbol
ANTLRInputStream input = new ANTLRInputStream(System.in);
                             ^
symbol:   class ANTLRInputStream
location: class antlr_test
antlr_test.java:10: error: cannot find symbol
    CommonTokenStream tokens = new CommonTokenStream(lexer);
    ^

符号：类 CommonTokenStream 位置：类 antlr_test antlr_test.java:10：错误：找不到符号 CommonTokenStream tokens = new CommonTokenStream(lexer); ^ 符号：类 CommonTokenStream 位置：类 antlr_test antlr_test.java:14：错误：找不到符号 parser.prog()；^ 符号：方法 prog() 位置：exprParser 7 类型的变量解析器错误`

标签： javaantlr4