经常遇到springboot打包jar后，因业务需要，比如文件上传模板存放到resources资源目录，本地开发环境能访问，但是打包jar部署到线上时却用不了了，下面是几种打包jar后也能访问的几种方式
package org.example.controller;
import org.example.utils.DownloadUtil;
import org.springframework.context.ApplicationContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.io.IOException;
import java.io.InputStream;
@RestController
@RequestMapping("/file")
public class FileController {
@javax.annotation.Resource
private ResourceLoader resourceLoader;
@javax.annotation.Resource
private ApplicationContext applicationContext;
@GetMapping("/1")
public void file1() {
InputStream inputStream = getClass().getClassLoader().getResourceAsStream("file/1.txt");
DownloadUtil.download(inputStream, "1.txt");
}
@GetMapping("/2")
public void file2() {
InputStream inputStream = getClass().getResourceAsStream("/file/2.txt");
DownloadUtil.download(inputStream, "2.txt");
}
@GetMapping("/3")
public void file3() throws IOException {
Resource resource = resourceLoader.getResource("classpath:/file/3.txt");
InputStream inputStream = resource.getInputStream();
DownloadUtil.download(inputStream, "3.txt");
}
@GetMapping("/4")
public void file4() throws IOException {
Resource resource = applicationContext.getResource("classpath:file/4.txt");
InputStream inputStream = resource.getInputStream();
DownloadUtil.download(inputStream, "4.txt");
}
@GetMapping("/5")
public void file5() throws IOException {
ClassPathResource resource = new ClassPathResource("file/5.txt");
DownloadUtil.download(resource.getInputStream(), "5.txt");
}
}