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如何利用java實現(xiàn)生成PDF文件

更新時間：2022年10月13日 09:51:37 作者：xhga

前段時間因為相關(guān)業(yè)務(wù)需求需要后臺生成pdf文件,下面這篇文章主要給大家介紹了關(guān)于如何利用java實現(xiàn)生成PDF文件的相關(guān)資料,文中通過實例代碼介紹的非常詳細(xì),需要的朋友可以參考下

1.PDF文件簡介

PDF是可移植文檔格式，是一種電子文件格式，具有許多其他電子文檔格式無法相比的優(yōu)點(diǎn)。PDF文件格式可以將文字、字型、格式、顏色及獨(dú)立于設(shè)備和分辨率的圖形圖像等封裝在一個文件中。該格式文件還可以包含超文本鏈接、聲音和動態(tài)影像等電子信息，支持特長文件，集成度和安全可靠性都較高。在系統(tǒng)開發(fā)中通常用來生成比較正式的報告或者合同類的電子文檔。

2.生成PDF

2.1 基于freemarker框架實現(xiàn)HTML轉(zhuǎn)PDF

2.1.1 引入jar包依賴:

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.20</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.itextpdf/html2pdf -->
<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>html2pdf</artifactId>
    <version>4.0.3</version>
</dependency>
<!-- spring boot 項目請?zhí)砑哟艘蕾?-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-freemarker</artifactId>
</dependency>
<!-- 非spring boot 項目請?zhí)砑哟艘蕾?-->
<dependency>
    <groupId>org.freemarker</groupId>
    <artifactId>freemarker</artifactId>
    <version>2.3.30</version>
</dependency>

2.1.2 創(chuàng)建html模板test_template：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8"/>
    <title>Title</title>
    <style>
        body{font-family:SimSun;}
        .title{align-content: center;text-align: center;}
        .signature{float:right }
    </style>
</head>
<body>
<div>
    <h1 class="title">標(biāo)題</h1>
    <h4 class="title">副標(biāo)題</h4>
    <span>當(dāng)前時間: ${date_time} </span>
    <div class="signature">日期：${date}</div>
</div>
</body>
</html>

2.1.3 獲取HTML內(nèi)容

當(dāng)HTML模板存放在系統(tǒng)文件夾

String templateDirectory = "D:\\";  // 系統(tǒng)文件夾路徑 如: D:\

當(dāng)HTML模板存放在項目resources/templates目錄

ClassLoader classLoader = PdfUtilTest.class.getClassLoader();
URL resource = classLoader.getResource("templates");
String templateDirectory = resource.toURI().getPath();

示例代碼:

import com.itextpdf.html2pdf.ConverterProperties;
import com.itextpdf.html2pdf.HtmlConverter;
import com.itextpdf.layout.font.FontProvider;
import freemarker.template.Configuration;
import freemarker.template.Template;
import lombok.extern.slf4j.Slf4j;

import java.io.*;
import java.net.URL;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.HashMap;
import java.util.Map;

@Slf4j
public class PdfUtilTest {
    /**
     * 獲取模板內(nèi)容
     * @param templateDirectory 模板文件夾
     * @param templateName      模板文件名
     * @param paramMap          模板參數(shù)
     * @return
     * @throws Exception
     */
    private static String getTemplateContent(String templateDirectory, String templateName, Map<String, Object> paramMap) throws Exception {
        Configuration configuration = new Configuration(Configuration.DEFAULT_INCOMPATIBLE_IMPROVEMENTS);
        try {
            configuration.setDirectoryForTemplateLoading(new File(templateDirectory));
        } catch (Exception e) {
            System.out.println("-- exception --");
        }

        Writer out = new StringWriter();
        Template template = configuration.getTemplate(templateName,"UTF-8");
        template.process(paramMap, out);
        out.flush();
        out.close();
        return out.toString();
    }
    public static void main(String[] args) throws Exception {
        Map<String, Object> paramMap = new HashMap<>();
        DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
        paramMap.put("date_time", dateTimeFormatter.format(LocalDateTime.now()));
        paramMap.put("date", dateTimeFormatter.format(LocalDateTime.now()).substring(0, 10));
        ClassLoader classLoader = PdfUtilTest.class.getClassLoader();
        URL resource = classLoader.getResource("templates");
        String templateDirectory  =resource.toURI().getPath();
        String templateContent = PdfUtilTest.getTemplateContent(templateDirectory, "test_template.html", paramMap);
        System.out.println(templateContent);
    }
}

2.1.4 生成PDF文檔

示例代碼:

    /**
     * HTML 轉(zhuǎn) PDF
     * @param content html內(nèi)容
     * @param outPath           輸出pdf路徑
     * @return 是否創(chuàng)建成功
     */
    public static boolean html2Pdf(String content, String outPath) {
        try {
            ConverterProperties converterProperties = new ConverterProperties();
            converterProperties.setCharset("UTF-8");
            FontProvider fontProvider = new FontProvider();
            fontProvider.addSystemFonts();
            converterProperties.setFontProvider(fontProvider);
            HtmlConverter.convertToPdf(content, new FileOutputStream(outPath), converterProperties);
        } catch (Exception e) {
            log.error("生成模板內(nèi)容失敗,{}",e);
            return false;
        }
        return true;
    }
    /**
     * HTML 轉(zhuǎn) PDF
     * @param content html內(nèi)容
     * @return PDF字節(jié)數(shù)組
     */
    public static byte[] html2Pdf(String content) {
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();;
        try {
            ConverterProperties converterProperties = new ConverterProperties();
            converterProperties.setCharset("UTF-8");
            FontProvider fontProvider = new FontProvider();
            fontProvider.addSystemFonts();
            converterProperties.setFontProvider(fontProvider);
            HtmlConverter.convertToPdf(content,outputStream,converterProperties);
        } catch (Exception e) {
            log.error("生成 PDF 失敗,{}",e);
        }
        return outputStream.toByteArray();
    }
	public static void main(String[] args) throws Exception {
	    Map<String, Object> paramMap = new HashMap<>();
	    DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
	    paramMap.put("date_time", dateTimeFormatter.format(LocalDateTime.now()));
	    paramMap.put("date", dateTimeFormatter.format(LocalDateTime.now()).substring(0, 10));
	    String outPath = "D:\\A.pdf";
	    String templateDirectory = "D:\\";
	    String templateContent = PdfUtilTest.getTemplateContent(templateDirectory, "test_template.html", paramMap);
	    PdfUtilTest.html2Pdf(templateContent, outPath);
	    
	}