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Java 字符串根据宽度(像素)换行

在一些场景下，我们经常会通过判断字符串的长度，比如个数来实现换行，但是中文、英文、数字、其实在展示的时候同样长度的字符串，其实它的宽度是不一样的，这也是们我通俗意义上说的宽度(像素) 。

根据像素宽度进行换行

需求:

/**   * 10、自己做图片 ，根据文本宽度进行换行   */  @Test  public void creatMyImage(){      //整体图合成      BufferedImage bufferedImage = new BufferedImage(500, 500, BufferedImage.TYPE_INT_RGB);      //设置图片的背景色      Graphics2D main = bufferedImage.createGraphics();      main.fillRect(0, 0, 500, 500);      String text = "111122223所以比传统纸巾更环保3334441比传统纸巾更环11111111111111122223所以比传统纸巾更环保3334441比传统纸巾更环11111111111111122223所以比传统纸巾更环保3334441比传统纸巾更环11111111111111122223所以比传统纸巾更环保3334441比传统纸巾更环11111111111";      Graphics2D textG = bufferedImage.createGraphics() ;      textG.setColor(new Color(37,37,37));      Font hualaoContentFont = new Font("PingFang SC", Font.PLAIN, 20);      textG.setFont(hualaoContentFont);      textG.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_GASP);      drawString(textG,text,30,100,4,10,50,true,false);      //存储到本地      String saveFilePath = "/Users/healerjean/Desktop/new.png";      saveImageToLocalDir(bufferedImage, saveFilePath);  }  /**   *   * @param g   * @param text 文本   * @param lineHeight 行高（注意字体大小的控制哦）   * @param maxWidth 行宽   * @param maxLine 最大行数   * @param left 左边距 //整段文字的左边距   * @param top 上边距 //整顿文字的上边距   * @param trim 是否修剪文本（1、去除首尾空格，2、将多个换行符替换为一个）   * @param lineIndent 是否首行缩进   */  public static void drawString(Graphics2D g, String text, float lineHeight, float maxWidth, int maxLine, float left,                                float top, boolean trim, boolean lineIndent) {      if (text == null || text.length() == 0) return;      if(trim) {          text = text.replaceAll("\\n+", "\n").trim();      }      if(lineIndent) {          text = "　　" + text.replaceAll("\\n", "\n　　");      }      drawString(g, text, lineHeight, maxWidth, maxLine, left, top);  }  /**   *   * @param g   * @param text 文本   * @param lineHeight 行高   * @param maxWidth 行宽   * @param maxLine 最大行数   * @param left 左边距   * @param top 上边距   */  private static void drawString(Graphics2D g, String text, float lineHeight, float maxWidth, int maxLine, float left,                                 float top) {      if (text == null || text.length() == 0) return;      FontMetrics fm = g.getFontMetrics();      StringBuilder sb = new StringBuilder();      for (int i = 0; i < text.length(); i++) {          char c = text.charAt(i);          sb.append(c);          int stringWidth = fm.stringWidth(sb.toString());          if (c == '\n' || stringWidth > maxWidth) {              if(c == '\n') {                  i += 1;              }              if (maxLine > 1) {                  g.drawString(text.substring(0, i), left, top);                  drawString(g, text.substring(i), lineHeight, maxWidth, maxLine - 1, left, top + lineHeight);              } else {                  g.drawString(text.substring(0, i - 1) + "…", left, top);              }              return;          }      }      g.drawString(text, left, top);  }

  。

Java字符串根据宽度(像素)进行换行及Pdf合并

实际开发中，我们经常会通过判断字符串的长度，比如个数来实现换行，但是中文、英文、数字在展示的时候同样长度的字符串，其实它的宽度是不一样的，这也是们我通俗意义上说的宽度(像素).

下面结合jasper套打打印业务来说明.

1、工具类最终版前奏

package main; import java.awt.Color;import java.awt.Font;import java.awt.FontMetrics;import java.awt.Graphics2D;import java.awt.RenderingHints;import java.awt.image.BufferedImage;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.FileOutputStream;import java.io.InputStream;import java.io.OutputStream; import javax.imageio.ImageIO;import javax.imageio.stream.ImageOutputStream; public class SubstringStr {	/**	 * 1、自己做图片，根据文本宽度进行换行	 */	public void creatMyImage(String text) {		// 整体图合成		BufferedImage bufferedImage = new BufferedImage(595, 842, BufferedImage.TYPE_INT_RGB);		// 设置图片的背景色		Graphics2D main = bufferedImage.createGraphics();		main.fillRect(0, 0, 1500, 2600);		Graphics2D graphics2d = bufferedImage.createGraphics();		graphics2d.setColor(new Color(37, 37, 37));		Font hualaoContentFont = new Font("宋体", Font.PLAIN, 20);		graphics2d.setFont(hualaoContentFont);		graphics2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_GASP);				drawString1(graphics2d, text, 30, 500, 28, 71, 20, false, false, 0);		// 存储到本地		String saveFilePath = "D:\\new.png";		saveImageToLocalDir(bufferedImage, saveFilePath);	}	private void saveImageToLocalDir(BufferedImage img, String saveFilePath) {			try {			//bufferedimage 转换成 inputstream			ByteArrayOutputStream bs = new ByteArrayOutputStream(); 			ImageOutputStream imOut = ImageIO.createImageOutputStream(bs); 			ImageIO.write(img, "jpg", imOut); 			InputStream inputStream = new ByteArrayInputStream(bs.toByteArray());			long length = imOut.length();						OutputStream outStream = new FileOutputStream(saveFilePath);						//输出流		    byte[] bytes = new byte[1024];		    long count = 0;		    while(count < length){		        int len = inputStream.read(bytes, 0, 1024);		        count +=len;		        outStream.write(bytes, 0, len);		    }		    outStream.flush();			inputStream.close();			outStream.close();		} catch (Exception e) {			e.printStackTrace();		}	}	/**	 * @param graphics2d	 * @param text  文本	 * @param lineHeight 行高（注意字体大小的控制哦）	 * @param maxWidth 行宽	 * @param maxLine  最大行数	 * @param left 左边距 //整段文字的左边距	 * @param top 上边距 //整段文字的上边距	 * @param trim  是否修剪文本（1、去除首尾空格，2、将多个换行符替换为一个）	 * @param lineIndent 是否首行缩进	 */	public static void drawString1(Graphics2D graphics2d, String text, float lineHeight, float maxWidth, int maxLine, float left,			float top, boolean trim, boolean lineIndent, int resultLine) {		if (text == null || text.length() == 0)			return;		if (trim) {			text = text.replaceAll("\\n+", "\n").trim();			System.err.println("执行了。。。。");		}		if (lineIndent) {			text = "　　" + text.replaceAll("\\n", "\n　　");			System.err.println("执行了=====");		}		drawString2(graphics2d, text, lineHeight, maxWidth, maxLine, left, top, resultLine);	} 	/**	 *	 * @param graphics2d	 * @param text 文本	 * @param lineHeight 行高	 * @param maxWidth 行宽	 * @param maxLine 最大行数	 * @param left 左边距	 * @param top 上边距	 */	private static void drawString2(Graphics2D graphics2d, String text, float lineHeight, float maxWidth, int maxLine,			float left, float top, int resultLine) {				if (text == null || text.length() == 0) {			return;		}		FontMetrics fm = graphics2d.getFontMetrics();		StringBuilder sb = new StringBuilder();				for (int i = 0; i < text.length(); i++) {			char strChar = text.charAt(i);			sb.append(strChar);						int stringWidth = fm.stringWidth(sb.toString());						if (strChar == '\n' || stringWidth > maxWidth) {				if (strChar == '\n') {					i += 1;					System.out.println("\n字符串内容为：" + text.substring(0, i));				}				if (maxLine > 1) {					resultLine = resultLine + 1;					System.err.println("\nif中字符串内容为：" + text.substring(0, i));					graphics2d.drawString(text.substring(0, i), left, top);										drawString2(graphics2d, text.substring(i), lineHeight, maxWidth, maxLine - 1, left, top + lineHeight, resultLine);									} else {					System.err.println("\nelse中字符串内容为：" + text.substring(0, i));					graphics2d.drawString(text.substring(0, i - 1) + "…", left, top);				}				return;			}		}		System.err.println("最后字符串内容为：" + text + "===行数为：" + resultLine);		graphics2d.drawString(text, left, top);	}		public static void main(String[] args) {		String text = "111122223所以比传统纸巾更环保3334441比传统纸巾更环11111111111111122223所以比传统纸巾更环保3334441比传统纸巾"				+ System.getProperty("line.separator") + "更环66666666"+ System.getProperty("line.separator") 				+ "所以比传统纸巾更环保3334441比传统纸巾更环。。。。。。。"				+ "111111122223所以比传统纸巾更环保3334441比传统纸巾更环11111111111"; 		SubstringStr test = new SubstringStr();		test.creatMyImage(text);				System.out.println("输入图片完成：D:/new.png");	} }

2、工具类最终版

package com.sinosoft.emr.util; import java.awt.Color;import java.awt.Font;import java.awt.FontMetrics;import java.awt.Graphics2D;import java.awt.RenderingHints;import java.awt.image.BufferedImage;import java.util.LinkedHashMap;import java.util.Map;import java.util.regex.Matcher;import java.util.regex.Pattern; public class SubstrUtil {	private static int index = 0;		/**	 * 1、自己做图片 ，根据文本宽度进行换行	 */	public static Map<String, Object> creatMyImage(String text, Font font, int appointRow, Map<String, Object> map, int rows) {		index = 0;		// 整体图合成		BufferedImage bufferedImage = new BufferedImage(595, 842, BufferedImage.TYPE_INT_RGB);		Graphics2D graphics2d = bufferedImage.createGraphics();		graphics2d.setColor(new Color(37, 37, 37));				graphics2d.setFont(font);		graphics2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_GASP);		map = myDrawString(graphics2d, text, 30, 500, appointRow, 71, 20, map, rows);				return map;	}			/**	 * 2、根据宽度截取字符串	 * @param graphics2d	 * @param text 文本	 * @param lineHeight 行高	 * @param maxWidth 行宽	 * @param maxLine 最大行数	 * @param left 左边距	 * @param top 上边距	 */	private static Map<String, Object> myDrawString(Graphics2D graphics2d, String text, int lineHeight, int maxWidth,			int maxLine, int left, int top, Map<String, Object> map, int rows) {		if (text == null || text.length() == 0) {			return map;		}		FontMetrics fm = graphics2d.getFontMetrics();		StringBuilder sb = new StringBuilder();				for (int i = 0; i < text.length(); i++) {			char strChar = text.charAt(i);			sb.append(strChar);						int stringWidth = fm.stringWidth(sb.toString());			int strLength = text.substring(0, i).length();						if (strLength >= 53 || strChar == '\n' || stringWidth >= maxWidth) {				if (strChar == '\n') {					i += 1;//					System.out.println("字符串内容为：" + text.substring(0, i));				}				if (maxLine > 1) {					rows = rows + 1;//					System.err.println("if中字符串内容为：" + text.substring(0, i));										char value = ' ', value1 = ' ';					try {						value = text.substring(i).charAt(0);						value1 = text.substring(i - 1).charAt(0);					} catch (Exception e) {						/*e.printStackTrace();*/						System.err.println("----" + e.getMessage());					}					if (isChinesePunctuation(value) && checkCharCN(value1)) {						map.put("row" + rows, text.substring(0, i - 1)); 						myDrawString(graphics2d, text.substring(i - 1), lineHeight, maxWidth, maxLine - 1, left, top + lineHeight, map, rows);											} else {						map.put("row" + rows, text.substring(0, i)); 						myDrawString(graphics2d, text.substring(i), lineHeight, maxWidth, maxLine - 1, left, top + lineHeight, map, rows);					}					index = index + i;					map.put("index", index);//					System.err.println("---下标" + index);				} else {					rows = rows + 1;					map.put("row" + rows, text.substring(0, i));//					System.err.println("else中字符串内容为：" + text.substring(0, i));										index = index + i;					map.put("index", index);				}								return map;			}		}				return map;	}		// 2.1 判断字符是否是中文	public static boolean checkCharCN(char c) {		String s = String.valueOf(c);		String regex = "[\u4e00-\u9fa5]";		Pattern p = Pattern.compile(regex);		Matcher m = p.matcher(s);		return m.matches();	}	// 2.2 判断字符是否是中文标点符号	public static boolean isChinesePunctuation(char c) {		Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);				if (ub == Character.UnicodeBlock.GENERAL_PUNCTUATION || ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION				|| ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS				|| ub == Character.UnicodeBlock.CJK_COMPATIBILITY_FORMS				|| ub == Character.UnicodeBlock.VERTICAL_FORMS) {			return true;					} else {			return false;		}	}			/**	 * 3、针对jasper中宽度较短的文本	 * @author wanglong	 * @date   2020年11月10日下午7:12:14	 */	public static Map<String, Object> creatShortImage(String text, Font font, int appointRow, Map<String, Object> map, int rows) {		index = 0;		// 整体图合成		BufferedImage bufferedImage = new BufferedImage(595, 842, BufferedImage.TYPE_INT_RGB);		// 设置图片的背景色		Graphics2D main = bufferedImage.createGraphics();		main.fillRect(0, 0, 595, 842);		Graphics2D graphics2d = bufferedImage.createGraphics();		graphics2d.setColor(new Color(37, 37, 37));				graphics2d.setFont(font);		graphics2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_GASP);				map = myDrawShortString(graphics2d, text, 30, 230, appointRow, 71, 20, map, rows);				return map;	}	// 3.1	private static Map<String, Object> myDrawShortString(Graphics2D graphics2d, String text, int lineHeight, int maxWidth, 			int maxLine, int left, int top, Map<String, Object> map, int rows) {		if (text == null || text.length() == 0) {			return map;		}		FontMetrics fm = graphics2d.getFontMetrics();		StringBuilder sb = new StringBuilder();				for (int i = 0; i < text.length(); i++) {			char strChar = text.charAt(i);			sb.append(strChar);						int stringWidth = fm.stringWidth(sb.toString());						if (strChar == '\n' || stringWidth > maxWidth) {				if (strChar == '\n') {					i += 1;					//System.out.println("字符串内容为：" + text.substring(0, i));				}				if (maxLine > 1) {					rows = rows + 1;					//System.err.println("if中字符串内容为：" + text.substring(0, i));					map.put("row" + rows, text.substring(0, i));					map.put("row_len" + rows, stringWidth);										myDrawShortString(graphics2d, text.substring(i), lineHeight, maxWidth, maxLine - 1, left, top + lineHeight, map, rows);									} else {					rows = rows + 1;					map.put("row" + rows, text.substring(0, i));					map.put("row_len" + rows, stringWidth);					//System.err.println("else中字符串内容为：" + text.substring(0, i));				}								return map;			}		}				return map;	} 	public static void main(String[] args) {		Map<String, Object> map = new LinkedHashMap<>();		int rows = 0;				int appointRow = 4;		Font font = new Font("宋体", Font.PLAIN, 12);				String text = "111122223所以比传统纸巾更环保3334441比传统纸巾更环11111111111111122223所以比传统纸巾更环保3334441测试数据"				+ System.getProperty("line.separator") + "在仿苹果官网垃圾桶时， 设计出的UI使用PingFang SC 字体"+ System.getProperty("line.separator") 				+ "天津市防控指挥部消息称,经排查,滨海新区中新天津纸巾更环保3334441比传统纸巾更环666所以比传统纸巾更环保3334441比传统纸巾更环8888";		int length = text.length();				map = creatMyImage(text, font, appointRow, map, rows);				if (length > index) {			System.out.println("还剩余文本：" + text.substring(index));		}				System.out.println("\n<<--->>>rows=" + rows + ", map="+map);	} }

说明：此工具类我们经理进行了改造，生成的文本内容符合中国人的书写习惯：行首不能是标点符号。如果行首是标点符号，上一行的最后一个文字会挪至本行.

3、项目中具体使用

3.1 controller层

/*** 4、打印 病程记录* @author wanglong* @date 2020年3月4日 下午5:22:57*/@RequestMapping(value = "printEmrCourse", method = RequestMethod.GET, produces = MediaType.APPLICATION_PDF_VALUE)public void printEmrCourse(@RequestParam(value = "id", required = true) String id,		@RequestParam(value = "courseType", required = true) String courseType,		@RequestParam(value = "token", required = true) String token, HttpServletResponse response) {	List<String> filePathList = new ArrayList<String>();			Map<String, Map<String, Object>> map = iEmrCourseSelectBusi.selectEmrCourseData(id, courseType, token);	try {		if (map.size() > 0) {			for (int i = 0, len = map.size(); i < len; i++) {				if (i % 2 == 0) {					String path1 = iEmrCourseSelectBusi.getCoursePdf(map.get("map" + i), "emrCourseLeft.jasper");					if (!"".equals(path1)) {						filePathList.add(path1);					}				} else {					String path2 = iEmrCourseSelectBusi.getCoursePdf(map.get("map" + i), "emrCourseRight.jasper");					if (!"".equals(path2)) {						filePathList.add(path2);					}				}			}							iEmrCourseSelectBusi.printEmrCoursePdf(filePathList, response);		}				} catch (Exception e) {		e.printStackTrace();	}}

3.2 serviceImpl层

@Service("iEmrCourseSelectBusi")public class EmrCourseBusiSelectImpl extends EmrCourseSelectServiceImpl implements IEmrCourseSelectBusi{	private static final long serialVersionUID = 1L;	private Font font = new Font("宋体", Font.PLAIN, 12);		// 读取配置文件里的jasper路径  @Value("${jasperPath}")  private String jasperPath;  /**   * 4、打印 病程记录   * @author wanglong   * @date   2020年11月9日下午3:49:23   */  @Override  public Map<String, Map<String, Object>> selectEmrCourseData(String id, String courseType, String token) {	    Map<String, Map<String, Object>> resultMap = new LinkedHashMap<>();	    Map<String, Object> map = new LinkedHashMap<>();	    int rows = 0, appointRow = 28;			    StringBuffer bufferStr = new StringBuffer();	    String lineBreak = System.getProperty("line.separator"); // 换行符			    try {		    EmrCourse record = emrCourseMapper.selectByPrimaryKey(id);		    if (record != null) {			    map.put("patientName", record.getPatientName());			    map.put("fkHosRegisterHosNo", record.getFkHosRegisterHosNo());							    String recordTime = DateUtil.dateToString(record.getCourseRecordTime(), "yyyy-MM-dd HH:mm");			    String doctorName = record.getDoctorRealName();							    if ("1".equals(courseType)) {				    bufferStr.append(recordTime + lineBreak);									    String tempStr = record.getGeneralRecords() == null ? "" : record.getGeneralRecords();				    String blankStr = "";				    if (!"".equals(tempStr)) {					    blankStr = StringDealUtil.getSubString(blankStr, tempStr);				    }									    String generalRecords = record.getGeneralRecords() == null ? "" : (blankStr + lineBreak);				    bufferStr.append(generalRecords);								    } 									    String updateName = record.getUpdateOprName();			    String opraterName = updateName == null ? record.getAddOprName() : updateName;			    bufferStr.append("\t\t\t\t\t\t\t\t\t签   名：" + opraterName + lineBreak);							    String text = bufferStr.toString();			    int length = text.length();							    map = SubstrUtil.creatMyImage(text, font, appointRow, map, rows);			    map.put("pageNum", "1");			    resultMap.put("map0", map);							    int index = (int) map.get("index");			    if (length > index) {				    String _text = StringDealUtil.getSurplusText(text, index);				    resultMap = this.getOtherMap(_text, appointRow, resultMap, 1);			    }		    }	    } catch (Exception e) {		e.printStackTrace();	    }			    return resultMap;  }	  // 4.1 截取文本获取其余map  private Map<String, Map<String, Object>> getOtherMap(String text, int appointRow,		    Map<String, Map<String, Object>> resultMap, int i) {	    int length = text.length();			    Map<String, Object> map = new LinkedHashMap<>();	    map = SubstrUtil.creatMyImage(text, font, appointRow, map, 0);	    map.put("pageNum", i + 1 + "");			    resultMap.put("map"+ i, map);			    int index = (int) map.get("index");	    if (length > index) {		    String _text = StringDealUtil.getSurplusText(text, index);		    resultMap = this.getOtherMap(_text, appointRow, resultMap, i+1);	    }			    return resultMap;  }   /**   * 5、生成pdf   * @author wanglong   * @date   2020年11月9日下午1:52:42   */  @Override  public String getCoursePdf(Map<String, Object> map, String jasperName) {	    String fileInfo = "";	    Instant timestamp = Instant.now();	    try {		    JRDataSource jrDataSource = new JRBeanCollectionDataSource(null);					    File reportFile = new File(jasperPath + jasperName);	        String exportFileName = timestamp.toEpochMilli() + ".pdf";	        fileInfo = jasperPath + exportFileName;	        	        //调用工具类	        JasperHelper.exportPdf2File(jasperPath + exportFileName, reportFile, map, jrDataSource);		        	    } catch (Exception e) {		    e.printStackTrace();	    }			    return fileInfo;  }  /**   * 5.1  合成pdf进行打印   * @author wanglong   * @date   2020年11月9日下午1:52:58   */  @Override  public void printEmrCoursePdf(List<String> filePathList, HttpServletResponse response) {	    List<File> files = new ArrayList<File>();	    try {	    	if (filePathList != null && filePathList.size() > 0) {		    	for (int i = 0, length = filePathList.size(); i < length; i++) {		    		String pathName = filePathList.get(i);		    		files.add(new File(pathName));		    	}						    	String newFileName = Instant.now().toEpochMilli() + "病程记录mul2one.pdf";			    String targetPath = jasperPath + newFileName;		    	File newFile = PdfMergeUtil.mulFile2One(files, targetPath);							    if (newFile.exists()) {			    	// 先将单个的pdf文件删除			    	for (File file : files) {			    		if (file.exists() && file.isFile()) {			    			file.delete();			    		}			    	}			    	newFile.getName();			    	PdfUtil.downloadFile(response, targetPath, newFileName);			    }		    }				    } catch (Exception e) {		e.printStackTrace();	    }  }}

4、工具类补充

package utils; import net.sf.jasperreports.engine.*;import net.sf.jasperreports.engine.util.JRLoader; import java.io.*;import java.util.Map; public class JasperHelper {	/**	 * 1、直接导出pdf文件	 * @author wanglong	 * @date   2020年10月31日下午9:10:41	 */	public static void exportPdf2File(String defaultFilename, File is, Map<String, Object> parameters, JRDataSource conn) {		try {			JasperReport jasperReport = (JasperReport) JRLoader.loadObject(is);			JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, parameters, conn);			exportPdfToFile(jasperPrint, defaultFilename);		} catch (Exception e) {			e.printStackTrace();		}	}		// 1.1 导出Pdf	private static void exportPdfToFile(JasperPrint jasperPrint, String defaultFilename) throws IOException, JRException {		FileOutputStream ouputStream = new FileOutputStream(new File(defaultFilename));		JasperExportManager.exportReportToPdfStream(jasperPrint, ouputStream);				ouputStream.flush();		ouputStream.close();	} }

package utils; import java.io.File;import java.io.IOException;import java.util.List; import org.apache.pdfbox.io.MemoryUsageSetting;import org.apache.pdfbox.multipdf.PDFMergerUtility; /*** @name: PdfMergeUtil* @Description: pdf合并拼接工具类* @author wanglong* @date   2020年2月25日下午4:33:13* @version 1.0*/public class PdfMergeUtil {	/**   * @Description: pdf合并拼接   * @param files 文件列表   * @param targetPath 合并到   * @throws IOException   */  public static File mulFile2One(List<File> files,String targetPath) throws IOException{      // pdf合并工具类      PDFMergerUtility mergePdf = new PDFMergerUtility();      for (File f : files) {          if(f.exists() && f.isFile()){              // 循环添加要合并的pdf              mergePdf.addSource(f);          }      }      // 设置合并生成pdf文件名称      mergePdf.setDestinationFileName(targetPath);      // 合并pdf      mergePdf.mergeDocuments(MemoryUsageSetting.setupMainMemoryOnly());            return new File(targetPath);  }}

package utils; import javax.servlet.http.HttpServletResponse;import java.io.*;/*** 导出PDF*/public class PdfUtil {  // 下载  public static void downloadFile(HttpServletResponse response, String filePath, String fileName) {		if (fileName != null) {			response.reset();			response.setContentType("application/pdf");						// 设置文件路径			File file = new File(filePath);			if (file.exists()) {				byte[] buffer = new byte[1024];				FileInputStream fis = null;				BufferedInputStream bis = null;				try {					fis = new FileInputStream(file);					bis = new BufferedInputStream(fis);					OutputStream os = response.getOutputStream();					int i = bis.read(buffer);					while (i != -1) {						os.write(buffer, 0, i);						i = bis.read(buffer);					}					System.out.println("download success!");									} catch (Exception e) {					e.printStackTrace();									} finally {                  if (bis != null) {                      try {                          bis.close();                      } catch (IOException e) {                          e.printStackTrace();                      }                  }                  if (fis != null) {                      try {                          fis.close();                      } catch (IOException e) {                          e.printStackTrace();                      }                  }              }              file.delete();          }      }  }}

以上为个人经验，希望能给大家一个参考，也希望大家多多支持我.

原文链接：https://blog.csdn.net/u012954706/article/details/81511216 。

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