原创

Spring Boot集成itext实现html生成PDF功能

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: 8088
spring:
  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
@SpringBootApplication
public 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;

@Data
public class Account {
    private String name;
    private String phoneNumber;
    private String email;
    private Address address;


}

package com.et.itextpdf.pojo;

import lombok.Data;

@Data
public 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;

@Data
public 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;

@Data
public 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;

@Data
public class Payment {
    private BigDecimal amount;
    private String cardNumber;
    private String cvv;
    private String month;
    private String year;
}