基于java实现zip文件下载，并添加水印

package com.research.business.controller;

import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.research.common.core.domain.AjaxResult;
import com.research.process.mapper.CityAndCountyMapper;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.common.PDRectangle;
import org.apache.pdfbox.pdmodel.font.PDType1Font;
import org.apache.pdfbox.pdmodel.graphics.state.PDExtendedGraphicsState;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.FileSystemResource;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

/**
 * @author zjl
 * @description TODO
 * @time: 2023/8/27 17:18
 */
@RestController
@RequestMapping("/downloadFile")
public class FileDownloadController {

    private static final Logger log = LoggerFactory.getLogger(FileDownloadController.class);

    @javax.annotation.Resource
    private CityAndCountyMapper cityAndCountyMapper;

    // 设置上传文件保存的目录
    @Value("${file.UPLOAD_DIR}")
    private String UPLOAD_DIR;

    @PostMapping("/download")
    public AjaxResult displayFile(@RequestBody JSONObject jsonObject, HttpServletResponse response) {
        try {
            //获取请求参数
            String cityId = jsonObject.getString("cityId");
            String userOa = jsonObject.getString("userOa");

            // 构建文件路径
            String directory = UPLOAD_DIR + "/pdf";
//            String directory = UPLOAD_DIR + "\\pdf";

            File dir = new File(directory);
            File targetFile = null;
            try {
                if (dir.isDirectory()) {
                    File[] files = dir.listFiles();
                    if (files != null) {
                        for (File file : files) {
                            if (file.isFile() && file.getName().contains(cityId)) {
                                targetFile = file;
                            }
                        }
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
                log.error("查询经营概况文档失败");
                return AjaxResult.error(500, "查询经营概况文档失败");
            }

            if (targetFile == null) {
                log.error("未查询到该地区经营概况文档");
                return AjaxResult.error(500, "未查询到该地区经营概况文档");
            }

            // 设置响应头信息
            response.setHeader(HttpHeaders.CONTENT_DISPOSITION, "inline; filename=" + URLEncoder.encode(targetFile.getName(), "UTF-8"));
            response.setContentType(MediaType.APPLICATION_PDF_VALUE);

            // 添加水印并获取带有水印的文件资源
            LocalDateTime currentDateTime = LocalDateTime.now();
            DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
            String formattedDateTime = currentDateTime.format(formatter);
            String watermarkText = userOa + " " + formattedDateTime + "           " + userOa + " " + formattedDateTime;

            // 创建PDF文档对象
            PDDocument document = PDDocument.load(targetFile);

            // 获取页面数量
            int pageCount = document.getNumberOfPages();

            // 创建水印图形状态
            PDExtendedGraphicsState graphicsState = new PDExtendedGraphicsState();
            graphicsState.setNonStrokingAlphaConstant(0.1f); // 设置非描边元素的透明度

            // 设置水印倾斜角度（以度为单位）
            float rotationAngle = 30;

            // 添加水印到每一页
            for (int i = 0; i < pageCount; i++) {
                PDPage page = document.getPage(i);

                // 获取页面大小和宽度
                PDRectangle mediaBox = page.getMediaBox();
                float pageWidth = mediaBox.getWidth();

                // 创建页面内容流
                PDPageContentStream contentStream = new PDPageContentStream(document, page, PDPageContentStream.AppendMode.APPEND, true, true);

                // 设置水印字体和大小
                contentStream.setFont(PDType1Font.HELVETICA_BOLD, 22);

                // 设置水印透明度
                contentStream.setGraphicsStateParameters(graphicsState);

                // 开始绘制水印
                contentStream.beginText();

                // 设置水印位置和倾斜角度
                contentStream.setTextMatrix(1, 0, 0, 1, 0, 0); // 原点在左下角
                contentStream.setTextRotation(Math.toRadians(rotationAngle), 100, 100); // 设置水印倾斜角度和起始位置

                // 添加水印文本
                for (int j = 0; j < 3; j++) {
                    contentStream.showText(watermarkText);
                    contentStream.newLineAtOffset(0, 200); // 移动到下一行的起始位置
                }
                // 结束绘制水印
                contentStream.endText();

                // 关闭内容流
                contentStream.close();
            }

            // 将带有水印的PDF文档写入响应流
            document.save(response.getOutputStream());
            document.close();
        } catch (IOException e) {
            log.error("解析经营概况文件失败");
            return AjaxResult.error("解析经营概况文件失败");
        }
        return null;
    }


    /**
     * @description 文件下载，单个文件直接下载，多个文件放入压缩包后下载
     * @author zjl91
     * @param[1] null
     * @time 2023/10/8 17:12
     */
    @PostMapping("/downloadPdf")
    public ResponseEntity<Resource> downloadFile(@RequestBody JSONObject jsonObject) throws IOException {
        // 构建文件路径
        String directory = UPLOAD_DIR + "/pdf/";
//        String directory = UPLOAD_DIR + "\\pdf\\";

        //解析传入的json数据
        JSONArray researchCountyList = jsonObject.getJSONArray("researchCountyList");
        String userOa = jsonObject.getString("userOa");

        //根据当前登录人账号和时间生成水印文本
        LocalDateTime currentDateTime = LocalDateTime.now();
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
        String formattedDateTime = currentDateTime.format(formatter);
        String watermarkText = userOa + " " + formattedDateTime + "           " + userOa + " " + formattedDateTime;

        if (researchCountyList.size() == 1) {
            //获取请求参数
            String cityId = (String) researchCountyList.get(0);

            File dir = new File(directory);
            File targetFile = null;

            if (dir.isDirectory()) {
                File[] files = dir.listFiles();
                if (files != null) {
                    for (File file : files) {
                        if (file.isFile() && file.getName().contains(cityId)) {
                            targetFile = file;
                        }
                    }
                }
            }

            //如果查询到对应的pdf文档，则进行下载
            if (!(targetFile == null)) {
                // 添加水印并获取带有水印的文件资源
                String filePath = directory + researchCountyList.get(0) + ".pdf";
                Resource resource = addWatermarkAndDownload(filePath, watermarkText, cityId);

                // 设置响应头
                HttpHeaders headers = new HttpHeaders();
                headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=" + directory + cityId + ".pdf");

                return ResponseEntity.ok()
                        .headers(headers)
                        .contentType(MediaType.APPLICATION_OCTET_STREAM)
                        .body(resource);
            } else {
                log.error("未查询到编码为" + cityId + "地市的经营概况文档！");
            }

        } else {
            File dir = new File(directory);

            // 创建临时压缩文件
            File zipFile = new File(UPLOAD_DIR + "/" + "files.zip");
//            File zipFile = new File("D:/research/temp/pdfs.zip");
            FileOutputStream fos = new FileOutputStream(zipFile);
            ZipOutputStream zos = new ZipOutputStream(fos);

            for (int i = 0; i < researchCountyList.size(); i++) {
                File targetFile = null;
                String cityId = researchCountyList.get(i).toString();
                if (dir.isDirectory()) {
                    File[] files = dir.listFiles();
                    if (files != null) {
                        for (File file : files) {
                            if (file.isFile() && file.getName().contains(cityId)) {
                                targetFile = file;
                            }
                        }
                    }
                }

                //如果查询到对应的pdf文档，则把文档放入压缩包中
                if (!(targetFile == null)) {
                    String filename = cityId + ".pdf";
                    Path file = Paths.get(directory + filename);

                    //根据地市编码获取地市的名称（重命名pdf文档的名称）
                    String cityName = cityAndCountyMapper.selectById(cityId);
                    String newFilename = cityName + ".pdf";

                    ZipEntry zipEntry = new ZipEntry(newFilename);
                    zos.putNextEntry(zipEntry);

                    // 添加水印并下载带有水印的PDF文件
                    Resource watermarkedPdf = addWatermarkAndDownload(file.toString(), watermarkText, cityId);
                    if (watermarkedPdf != null) {
                        Path watermarkedPdfPath = watermarkedPdf.getFile().toPath();
                        Files.copy(watermarkedPdfPath, zos);
                    }

                    zos.closeEntry();
                } else {
                    log.error("未查询到编码为" + researchCountyList.get(i) + "地市的经营概况文档！");
                }

            }

            //关闭流
            zos.close();
            fos.close();

            // 创建压缩包资源
            FileSystemResource resource = new FileSystemResource(zipFile);

            // 设置响应头
            HttpHeaders headers = new HttpHeaders();
            headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=pdfs.zip");

            return ResponseEntity.ok()
                    .headers(headers)
                    .contentType(MediaType.APPLICATION_OCTET_STREAM)
                    .body(resource);
        }
        return null;

    }


    /**
     * @description 给文件添加水印
     * @author zjl91
     * @param[1] String filePath   需要添加水印的文件路径
     * @param[2] String watermarkText   水印的内容（当前登录人账号+日期）
     * @param[3] String fileName   添加水印的文件名称（无后缀的）
     * @time 2023/10/9 9:32
     */
    private Resource addWatermarkAndDownload(String filePath, String watermarkText, String fileName) {
        try {
            // 加载PDF文档
            PDDocument document = PDDocument.load(new File(filePath));

            // 获取页面数量
            int pageCount = document.getNumberOfPages();

            // 创建水印图形状态
            PDExtendedGraphicsState graphicsState = new PDExtendedGraphicsState();
            graphicsState.setNonStrokingAlphaConstant(0.1f); // 设置非描边元素的透明度

            // 设置水印倾斜角度（以度为单位）
            float rotationAngle = 30;

            // 添加水印到每一页
            for (int i = 0; i < pageCount; i++) {
                PDPage page = document.getPage(i);

                // 获取页面大小和宽度
                PDRectangle mediaBox = page.getMediaBox();
                float pageWidth = mediaBox.getWidth();

                // 创建页面内容流
                PDPageContentStream contentStream = new PDPageContentStream(document, page, PDPageContentStream.AppendMode.APPEND, true, true);

                // 设置水印字体和大小
                contentStream.setFont(PDType1Font.HELVETICA_BOLD, 22);

                // 设置水印透明度
                contentStream.setGraphicsStateParameters(graphicsState);

                // 开始绘制水印
                contentStream.beginText();

                // 设置水印位置和倾斜角度
                contentStream.setTextMatrix(1, 0, 0, 1, 0, 0); // 原点在左下角
                contentStream.setTextRotation(Math.toRadians(rotationAngle), 100, 100); // 设置水印倾斜角度和起始位置

                // 添加水印文本，三行
                for (int j = 0; j < 3; j++) {
                    contentStream.showText(watermarkText);
                    contentStream.newLineAtOffset(0, 200); // 移动到下一行的起始位置
                }

                // 结束绘制水印
                contentStream.endText();

                // 关闭内容流
                contentStream.close();
            }

            // 构建文件路径
            String directory = UPLOAD_DIR + "/watermarkedPdf/";
            File targetDirectoryFile = new File(directory);
            //当转存路径不存在时，生成转存路径(用于保存添加了水印的文件)
            if (!targetDirectoryFile.exists()) {
                targetDirectoryFile.mkdirs();
            }

            // 保存修改后的PDF文件
            String watermarkedFilePath = directory + fileName + "_watermarked.pdf";
            document.save(watermarkedFilePath);

            // 关闭文档
            document.close();

            // 创建文件资源
            return new FileSystemResource(watermarkedFilePath);
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }

}