1.itext介绍

iText是著名的开放源码的站点sourceforge一个项目，是用于生成PDF文档的一个java类库。通过iText不仅可以生成PDF或rtf的文档，而且可以将XML、Html文件转化为PDF文件

iText 的特点

以下是 iText 库的显着特点 −

Interactive − iText 为你提供类（API）来生成交互式 PDF 文档。使用这些，你可以创建地图和书籍。
Adding bookmarks, page numbers, etc − 使用 iText，你可以添加书签、页码和水印。
Split & Merge − 使用 iText，你可以将现有的 PDF 拆分为多个 PDF，还可以向其中添加/连接其他页面。
Fill Forms − 使用 iText，你可以在 PDF 文档中填写交互式表单。
Save as Image − 使用 iText，你可以将 PDF 保存为图像文件，例如 PNG 或 JPEG。
Canvas − iText 库为您提供了一个 Canvas 类，你可以使用它在 PDF 文档上绘制各种几何形状，如圆形、线条等。
Create PDFs − 使用 iText，你可以从 Java 程序创建新的 PDF 文件。你也可以包含图像和字体。

2.代码工程

实验目标：将thymeleaf 的views生成成PDF

pom.xml

<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0"         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">    <parent>        <artifactId>springboot-demo</artifactId>        <groupId>com.et</groupId>        <version>1.0-SNAPSHOT</version>    </parent>    <modelVersion>4.0.0</modelVersion>
    <artifactId>itextpdf</artifactId>
    <properties>        <maven.compiler.source>8</maven.compiler.source>        <maven.compiler.target>8</maven.compiler.target>    </properties>    <dependencies>
        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>
        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-autoconfigure</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-test</artifactId>            <scope>test</scope>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-thymeleaf</artifactId>        </dependency>        <dependency>            <groupId>com.itextpdf</groupId>            <artifactId>html2pdf</artifactId>            <version>3.0.1</version>        </dependency>        <dependency>            <groupId>com.itextpdf</groupId>            <artifactId>kernel</artifactId>            <version>7.1.12</version>        </dependency>        <dependency>            <groupId>org.projectlombok</groupId>            <artifactId>lombok</artifactId>        </dependency>    </dependencies></project>

application.yaml

server:  port: 8088spring:  thymeleaf:    cache: false

DemoApplication

package com.et.itextpdf;
import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.web.servlet.ServletComponentScan;
@ServletComponentScan@SpringBootApplicationpublic class DemoApplication {
   public static void main(String[] args) {      SpringApplication.run(DemoApplication.class, args);   }}

controller

converterProperties.setBaseUri 很重要。否则，像 /main.css 这样的静态资源将无法找到

package com.et.itextpdf.controller;
import com.et.itextpdf.pojo.Order;import com.et.itextpdf.util.OrderHelper;import com.itextpdf.html2pdf.ConverterProperties;import com.itextpdf.html2pdf.HtmlConverter;
import org.springframework.beans.factory.annotation.Autowired;import org.springframework.http.HttpHeaders;import org.springframework.http.MediaType;import org.springframework.http.ResponseEntity;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;import org.thymeleaf.TemplateEngine;import org.thymeleaf.context.WebContext;
import javax.servlet.ServletContext;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.ByteArrayOutputStream;import java.io.IOException;
@Controller@RequestMapping("/orders")public class PDFController {

    @Autowired    ServletContext servletContext;
    private final TemplateEngine templateEngine;
    public PDFController(TemplateEngine templateEngine) {        this.templateEngine = templateEngine;    }
    @RequestMapping(path = "/")    public String getOrderPage(Model model) {        Order order = OrderHelper.getOrder();        model.addAttribute("orderEntry", order);        return "order";    }
    @RequestMapping(path = "/pdf")    public ResponseEntity<?> getPDF(HttpServletRequest request, HttpServletResponse response) throws IOException {
        /* Do Business Logic*/
        Order order = OrderHelper.getOrder();
        /* Create HTML using Thymeleaf template Engine */
        WebContext context = new WebContext(request, response, servletContext);        context.setVariable("orderEntry", order);        String orderHtml = templateEngine.process("order", context);
        /* Setup Source and target I/O streams */
        ByteArrayOutputStream target = new ByteArrayOutputStream();        ConverterProperties converterProperties = new ConverterProperties();        converterProperties.setBaseUri("http://localhost:8088");        /* Call convert method */        HtmlConverter.convertToPdf(orderHtml, target, converterProperties);
        /* extract output as bytes */        byte[] bytes = target.toByteArray();

        /* Send the response as downloadable PDF */
        return ResponseEntity.ok()                .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=order.pdf")                .contentType(MediaType.APPLICATION_PDF)                .body(bytes);
    }
}

view

Spring MVC 带有模板引擎，可以提供动态的 HTML 内容。我们可以通过以下方法轻松将这些回复转换为 PDF 格式。在本例中，我导入了 spring-boot-starter-web 和 spring-boot-starter-thymeleaf 来为我的 spring boot 项目提供 MVC 和 thymeleaf 支持。您可以使用自己选择的模板引擎。看看下面这个thymeleaf模板内容。主要展示订单详细信息。另外，通过 OrderHelper 的辅助方法来生成一些虚拟订单内容。

<!doctype html><html lang="en" xmlns:th="http://www.thymeleaf.org"><head>    <meta charset="UTF-8">    <meta content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0"          name="viewport">    <meta content="ie=edge" http-equiv="X-UA-Compatible">    <title>Spring Boot - Thymeleaf</title>    <link th:href="@{/main.css}" rel="stylesheet"/></head><body class="flex items-center justify-center h-screen"><div class="rounded-lg border shadow-lg p-10 w-3/5">    <div class="flex flex-row justify-between pb-4">        <div>            <h2 class="text-xl font-bold">Order #<span class="text-green-600" th:text="${orderEntry.orderId}"></span>            </h2>        </div>        <div>            <div class="text-xl font-bold" th:text="${orderEntry.date}"></div>        </div>    </div>    <div class="flex flex-col pb-8">        <div class="pb-2">            <h2 class="text-xl font-bold">Delivery Address</h2>        </div>        <div th:text="${orderEntry.account.address.street}"></div>        <div th:text="${orderEntry.account.address.city}"></div>        <div th:text="${orderEntry.account.address.state}"></div>        <div th:text="${orderEntry.account.address.zipCode}"></div>
    </div>    <table class="table-fixed w-full text-right border rounded">        <thead class="bg-gray-100">        <tr>            <th class="text-left pl-4">Product</th>            <th>Qty</th>            <th>Price</th>            <th class="pr-4">Total</th>        </tr>        </thead>        <tbody>        <tr th:each="item : ${orderEntry.items}">            <td class="pl-4 text-left" th:text="${item.name}"></td>            <td th:text="${item.quantity}"></td>            <td th:text="${item.price}"></td>            <td class="pr-4" th:text="${item.price * item.quantity}"></td>        </tr>        </tbody>    </table>    <div class="flex flex-row-reverse p-5">        <h2 class="font-medium  bg-gray-200 p-2 rounded">            Grand Total: <span class="text-green-600" th:text="${orderEntry.payment.amount}"></span>        </h2>    </div>    <h2 class="text-xl font-bold">Payment Details</h2>    <table class="table-fixed text-left w-2/6 border">        <tr>            <th class="text-green-600">Card Number</th>            <td th:text="${orderEntry.payment.cardNumber}"></td>        </tr>        <tr>            <th class="text-green-600">CVV</th>            <td th:text="${orderEntry.payment.cvv}"></td>        </tr>        <tr>            <th class="text-green-600">Expires (MM/YYYY)</th>            <td th:text="${orderEntry.payment.month +'/'+ orderEntry.payment.year}"></td>        </tr>    </table></div></body></html>

POJO

package com.et.itextpdf.pojo;
import lombok.Data;
@Datapublic class Account {    private String name;    private String phoneNumber;    private String email;    private Address address;

}

package com.et.itextpdf.pojo;
import lombok.Data;
@Datapublic class Address {    private String street;    private String city;    private String state;    private String zipCode;}

package com.et.itextpdf.pojo;
import lombok.Data;
import java.math.BigDecimal;
@Datapublic class Item {    private String sku;    private String name;    private Integer quantity;    private BigDecimal price;}

package com.et.itextpdf.pojo;
import lombok.Data;
import java.util.List;
@Datapublic class Order {    private Integer orderId;    private String date;    private Account account;    private Payment payment;    private List<Item> items;}

package com.et.itextpdf.pojo;
import lombok.Data;
import java.math.BigDecimal;
@Datapublic class Payment {    private BigDecimal amount;    private String cardNumber;    private String cvv;    private String month;    private String year;}

以上只是一些关键代码，所有代码请参见下面代码仓库

代码仓库

https://github.com/Harries/springboot-demo

3.测试

启动spring boot应用
访问http://127.0.0.1:8088/orders/,返回结果如下：

访问http://127.0.0.1:8088/orders/pdf,生成pdf并下载

4.引用

https://springhow.com/spring-boot-pdf-generation/
https://kb.itextpdf.com/itext/ebooks
http://www.liuhaihua.cn/archives/710362.html

ITPub博客

Spring Boot集成itext实现html生成PDF功能