Question

我是java的新手。我正在尝试创建一个项目，从所需的.java文件（HelloOOPP.java）获取类名，字段名。我成功获得了类名，但我对字段名称有疑问。

它返回以下文本而不是HelloOOPP类字段名称（输出）（我希望得到x和y字段）：

Class name:HelloOOPP
Fields:
NODE_BY_BEGIN_POSITION
ABSOLUTE_BEGIN_LINE
ABSOLUTE_END_LINE
SYMBOL_RESOLVER_KEY

App.java文件：

package com.app;
import java.io.File;
import java.io.FileNotFoundException;

public class App 
{
    public static void main(String[] args) throws FileNotFoundException  { 
   System.out.println(GetTypes.parseClassname(new File("C:\\HelloOOPP.java")));
    }
}

GetTypes.java文件：

package com.app;
import com.github.javaparser.*;
import com.github.javaparser.ast.*;
import com.github.javaparser.ast.CompilationUnit;
import com.github.javaparser.ast.body.*;
import java.io.*;
import java.lang.reflect.Field;
public class GetTypes {
    public static String parseClassname(File filename) throws FileNotFoundException   {
            FileInputStream fin = new FileInputStream(filename);
            CompilationUnit cu = JavaParser.parse(fin);
            StringBuilder build=new  StringBuilder();
            for (TypeDeclaration type : cu.getTypes())
            {
                if (type.isClassOrInterfaceDeclaration())
                { 
                    build.append("Class name:");
                    build.append(type.getName());
                    build.append("\n");
                    build.append("Fields:");
                    build.append("\n");
                    build.append(Get_Fields(type));                 
                }           
            }
            return build.toString();    
    }   
     private static StringBuilder Get_Fields(TypeDeclaration c) //Get all field names
     {
         Field[] fields = c.getClass().getFields();
         StringBuilder str=new StringBuilder();
         for(int i=0;i<fields.length;i++)
         {
             str.append(fields[i].getName());
             str.append("\n");
         }
         return str;
     }
     /*
     private int Count_Fields(TypeDeclaration c)
     {

     }*/    
}

HelloOOPP.java文件：

public class HelloOOPP
{
    public int x;
    public int y;
}

Answer 1

你正在混合使用Javaparser和经典反射。

写作时

Field[] fields = c.getClass().getFields();

，你得到的是TypeDeclaration类的字段，而不是HelloOOPP类（这就是为什么你会看到ABSOLUTE_BEGIN_LINE等意外的字段名称。）

根据问题How to get class level variable declarations using javaparser ? ，您的方法可能如下所示：

 private static StringBuilder Get_Fields(TypeDeclaration c) //Get all field names
 {
    List<BodyDeclaration> members = c.getMembers();
    StringBuilder str=new StringBuilder();

    if(members != null) {
        for (BodyDeclaration member : members) {

            //Check just members that are FieldDeclarations
            FieldDeclaration field = (FieldDeclaration) member;

            str.append(field.getVariables().get(0).getId().getName());
            str.append("\n");

        }

    }

     return str;
 }

如何在TypeDeclaration对象中获取字段名称？

1 个答案: