SpringBoot下获取resources目录下文件的常用方法

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>