spring 读取jar包内部的静态文件失败

package com.liu.springboot.controller;
import org.springframework.core.io.ClassPathResource;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import java.io.*;
/**
*将static中的favicon.ico 复制到D盘
*
*/
@Controller
public class TestFile {
    @RequestMapping("/getFile")
    @ResponseBody
    public String read() {
        ClassPathResource classPathResource = new ClassPathResource("static/favicon.ico");
        File copy = new File("D://copy.ico");
        OutputStream outputStream = null;
        InputStream inputStream = null;
        int len;
        byte[] buf = new byte[100];
        try {
            outputStream = new FileOutputStream(copy);
            File file = classPathResource.getFile();
            inputStream = new FileInputStream(file);
            while ((len = inputStream.read(buf))>0) {
                outputStream.write(buf,0,len);
            }
//            System.out.println("ok");
            return  "ok";
        }catch (IOException io) {
            return  "false";
        } finally {
            try {
                outputStream.close();
                inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

 outputStream = new FileOutputStream(copy);
//File file = classPathResource.getFile();
//inputStream = new FileInputStream(file);
//直接得到输入流
 inputStream = classPathResource.getInputStream();
 while ((len = inputStream.read(buf))>0) {
     outputStream.write(buf,0,len);
 }