meidu2021/daju/target/classes/cn/com/lzt/common/util/PdfUtil.java

package cn.com.lzt.common.util;


import com.lowagie.text.*;
import com.lowagie.text.pdf.PdfWriter;
import org.apache.commons.io.IOUtils;
import org.jeecgframework.core.util.ResourceUtil;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.Collections;
import java.util.List;

public class PdfUtil {
    public static PdfConfig defalutConfig = new DefaultPdfConfig();

    public static void generateToStream (List<Element> elementList, PdfConfig config, OutputStream outputStream){
        generateListToStream(Collections.singletonList(elementList),config,outputStream);
    }

    public static void generateListToStream(List<List<Element>> elementListCollection, PdfConfig config, OutputStream outputStream){
        if(config==null) config=defalutConfig;
        Document doc = new Document(config.getRect());
        PdfWriter writer =null;
        try {
            writer = PdfWriter.getInstance(doc,outputStream);
            doc.open();
//            doc.setMargins(10, 10, 10, 10);
            int i=0;
            for(List<Element> elementList:elementListCollection) {
                for (Element e : elementList) {
                    doc.add(e);
                }
                i++;
                if(i!=elementListCollection.size()) {
                    doc.newPage();
                }
            }
        } catch (DocumentException e) {
            e.printStackTrace();
        }finally {
            doc.close();
        }
    }

    //直接查看不下载
    public static void view(List<List<Element>> elementListCollection,HttpServletResponse response){
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        byte[] bytes = null;
        try{
            generateListToStream(elementListCollection,null,outputStream);
            bytes= outputStream.toByteArray();
            response.setContentType("application/pdf");
            response.setContentLength(bytes.length);
            response.getOutputStream().write(bytes);
            response.getOutputStream().flush();
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            IOUtils.closeQuietly(outputStream);
        }
    }

    public static void export(List<List<Element>> elementListCollection,HttpServletResponse response, String fileName)  {
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        byte[] bytes = null;
        try{
            generateListToStream(elementListCollection,null,outputStream);
            bytes= outputStream.toByteArray();
            if (isIE()) {
                fileName = java.net.URLEncoder.encode(fileName, "UTF-8");
            } else {
                fileName = new String(fileName.getBytes("UTF-8"), "ISO-8859-1");
            }
            response.setHeader("Content-Disposition", "attachment;filename="+  fileName +".pdf");
            response.setContentType("application/pdf");
            response.setContentLength(bytes.length);
            response.getOutputStream().write(bytes);
            response.getOutputStream().flush();
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            IOUtils.closeQuietly(outputStream);
        }
    }

   static boolean isIE() {
        HttpServletRequest request= ResourceUtil.getRequest();
        return (request.getHeader("USER-AGENT").toLowerCase().indexOf("msie") > 0 || request.getHeader("USER-AGENT").toLowerCase().indexOf("rv:11.0") > 0) ? true : false;
    }

    public static class PdfConfig{
        private Rectangle rect;
        public Rectangle getRect() {
            return rect;
        }

        public void setRect(Rectangle rect) {
            this.rect = rect;
        }
    }
    private static class DefaultPdfConfig extends PdfConfig{
        private static Rectangle DEFAULT_RECT = new Rectangle(PageSize.A4);
        public DefaultPdfConfig(){
            setRect(DEFAULT_RECT);
        }
    }
}