哈喽，大家好，今天给大家带来SpringBoot获取resources目录下文件的常用方法，示例中的方法是读取resources目录下的txt和xlsx文件，并将xlsx导出到excel的简单写法。完整代码放在最后。
通过this.getClass()方法获取
method1 - method4都是通过这个方法获取文件的写法，这四种写法在idea中都可以正常运行，jar包执行后method1和method2报错，提示找不到文件，method3和method4可以正常运行
通过ClassPathResource获取
method5是通过这种方法实现，idea中可以正常运行，打包后的jar中提示找不到文件
通过hutool工具类ResourceUtil获取
method6是通过这种方法实现，和method情况一样，同样是idea中可以正常运行，导出的jar中提示找不到文件
总结
不想折腾的同学可以直接用method3和method4的方法来使用，也可以将模板和资源文件外置，通过绝对路径获取对应文件。有好的方法也欢迎大家一起交流沟通~
代码
import cn.hutool.core.io.FileUtil;
import cn.hutool.core.io.resource.ClassPathResource;
import cn.hutool.core.io.resource.ResourceUtil;
import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.ExcelWriter;
import com.alibaba.excel.enums.WriteDirectionEnum;
import com.alibaba.excel.write.metadata.WriteSheet;
import com.alibaba.excel.write.metadata.fill.FillConfig;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import javax.servlet.http.HttpServletResponse;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.List;@RestController
@RequestMapping("/temp")
public class TemplateController {/*** this.getClass()方法获取* @param response* @throws IOException*/@RequestMapping("/method1")public void method1(HttpServletResponse response) throws IOException {System.out.println("----------method1 start");String filename = "template.xlsx";String bashPatch = this.getClass().getClassLoader().getResource("").getPath();System.out.println(bashPatch);String textFile = "template.txt";String textPath = this.getClass().getClassLoader().getResource("").getPath();List<String> dataList = FileUtil.readUtf8Lines(textPath + "/template/" + textFile);for (String data : dataList) {System.out.println(data);}try (ExcelWriter excelWriter =EasyExcel.write(response.getOutputStream()).autoCloseStream(false) // 不要自动关闭，交给 Servlet 自己处理
// .withTemplate(resource.getFile().getAbsolutePath()).withTemplate(bashPatch + "/template/" + filename).build()) {WriteSheet writeSheet = EasyExcel.writerSheet(0).build();FillConfig userFillConfig = FillConfig.builder().forceNewRow(Boolean.TRUE).build();FillConfig titleFillConfig = FillConfig.builder().direction(WriteDirectionEnum.HORIZONTAL).build();excelWriter.finish();}try {response.addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, StandardCharsets.UTF_8.name()));} catch (UnsupportedEncodingException e) {throw new RuntimeException(e);}response.setContentType("application/vnd.ms-excel;charset=UTF-8");}@RequestMapping("/method2")public void method2(HttpServletResponse response) throws IOException {System.out.println("----------method2 start");String filename = "template.xlsx";String bashPatch = this.getClass().getClassLoader().getResource("template").getPath();System.out.println(bashPatch);String textFile = "template.txt";String textPath = this.getClass().getClassLoader().getResource("template").getPath();List<String> dataList = FileUtil.readUtf8Lines(textPath + "/" + textFile);for (String data : dataList) {System.out.println(data);}try (ExcelWriter excelWriter =EasyExcel.write(response.getOutputStream()).autoCloseStream(false) // 不要自动关闭，交给 Servlet 自己处理
// .withTemplate(resource.getFile().getAbsolutePath()).withTemplate(bashPatch + "/" + filename).build()) {WriteSheet writeSheet = EasyExcel.writerSheet(0).build();FillConfig userFillConfig = FillConfig.builder().forceNewRow(Boolean.TRUE).build();FillConfig titleFillConfig = FillConfig.builder().direction(WriteDirectionEnum.HORIZONTAL).build();excelWriter.finish();}try {response.addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, StandardCharsets.UTF_8.name()));} catch (UnsupportedEncodingException e) {throw new RuntimeException(e);}response.setContentType("application/vnd.ms-excel;charset=UTF-8");}@RequestMapping("/method3")public void method3(HttpServletResponse response) throws IOException {System.out.println("----------method3 start");String filename = "template.xlsx";InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream("template" + "/" + filename);
// System.out.println(inputStream);String textFile = "template.txt";InputStream textStream = this.getClass().getClassLoader().getResourceAsStream("template" + "/" + textFile);BufferedReader reader = new BufferedReader(new InputStreamReader(textStream));String line;try {while ((line = reader.readLine()) != null) {System.out.println(line);}} catch (IOException e) {e.printStackTrace(); // 异常处理}try (ExcelWriter excelWriter =EasyExcel.write(response.getOutputStream()).autoCloseStream(false) // 不要自动关闭，交给 Servlet 自己处理
// .withTemplate(resource.getFile().getAbsolutePath()).withTemplate(inputStream).build()) {WriteSheet writeSheet = EasyExcel.writerSheet(0).build();FillConfig userFillConfig = FillConfig.builder().forceNewRow(Boolean.TRUE).build();FillConfig titleFillConfig = FillConfig.builder().direction(WriteDirectionEnum.HORIZONTAL).build();excelWriter.finish();}try {response.addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, StandardCharsets.UTF_8.name()));} catch (UnsupportedEncodingException e) {throw new RuntimeException(e);}response.setContentType("application/vnd.ms-excel;charset=UTF-8");}@RequestMapping("/method4")public void method4(HttpServletResponse response) throws IOException {System.out.println("----------method4 start");String filename = "template.xlsx";InputStream inputStream = this.getClass().getResourceAsStream("/template" + "/" + filename);
// System.out.println(inputStream);String textFile = "template.txt";InputStream textStream = this.getClass().getResourceAsStream("/template" + "/" + textFile);BufferedReader reader = new BufferedReader(new InputStreamReader(textStream));String line;try {while ((line = reader.readLine()) != null) {System.out.println(line);}} catch (IOException e) {e.printStackTrace(); // 异常处理}try (ExcelWriter excelWriter =EasyExcel.write(response.getOutputStream()).autoCloseStream(false) // 不要自动关闭，交给 Servlet 自己处理
// .withTemplate(resource.getFile().getAbsolutePath()).withTemplate(inputStream).build()) {WriteSheet writeSheet = EasyExcel.writerSheet(0).build();FillConfig userFillConfig = FillConfig.builder().forceNewRow(Boolean.TRUE).build();FillConfig titleFillConfig = FillConfig.builder().direction(WriteDirectionEnum.HORIZONTAL).build();excelWriter.finish();}try {response.addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, StandardCharsets.UTF_8.name()));} catch (UnsupportedEncodingException e) {throw new RuntimeException(e);}response.setContentType("application/vnd.ms-excel;charset=UTF-8");}/*** 通过ClassPathResource获取* @param response* @throws IOException*/@RequestMapping("/method5")public void method5(HttpServletResponse response) throws IOException {System.out.println("----------method5 start");String filename = "template.xlsx";ClassPathResource classPathResource = new ClassPathResource("template" + "/" + filename);String textFile = "template.txt";ClassPathResource textResource = new ClassPathResource("template" + "/" + textFile);List<String> dataList = FileUtil.readUtf8Lines(textResource.getAbsolutePath());for (String data : dataList) {System.out.println(data);}try (ExcelWriter excelWriter =EasyExcel.write(response.getOutputStream()).autoCloseStream(false) // 不要自动关闭，交给 Servlet 自己处理.withTemplate(classPathResource.getAbsolutePath()).build()) {WriteSheet writeSheet = EasyExcel.writerSheet(0).build();FillConfig userFillConfig = FillConfig.builder().forceNewRow(Boolean.TRUE).build();FillConfig titleFillConfig = FillConfig.builder().direction(WriteDirectionEnum.HORIZONTAL).build();excelWriter.finish();}try {response.addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, StandardCharsets.UTF_8.name()));} catch (UnsupportedEncodingException e) {throw new RuntimeException(e);}response.setContentType("application/vnd.ms-excel;charset=UTF-8");}/*** 通过hutool工具类ResourceUtil获取* @param response* @throws IOException*/@RequestMapping("/method6")public void method6(HttpServletResponse response) throws IOException {System.out.println("----------method6 start");String filename = "template.xlsx";String filePath = ResourceUtil.getResource("template" + "/" + filename).getPath();String textFile = "template.txt";String textPath = ResourceUtil.getResource("template" + "/" + textFile).getPath();List<String> dataList = FileUtil.readUtf8Lines(textPath);for (String data : dataList) {System.out.println(data);}try (ExcelWriter excelWriter =EasyExcel.write(response.getOutputStream()).autoCloseStream(false) // 不要自动关闭，交给 Servlet 自己处理.withTemplate(filePath).build()) {WriteSheet writeSheet = EasyExcel.writerSheet(0).build();FillConfig userFillConfig = FillConfig.builder().forceNewRow(Boolean.TRUE).build();FillConfig titleFillConfig = FillConfig.builder().direction(WriteDirectionEnum.HORIZONTAL).build();excelWriter.finish();}try {response.addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, StandardCharsets.UTF_8.name()));} catch (UnsupportedEncodingException e) {throw new RuntimeException(e);}response.setContentType("application/vnd.ms-excel;charset=UTF-8");}}
pom依赖
<dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.8.9</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>easyexcel</artifactId><version>3.3.3</version></dependency>
