SpringBoot(十五)_springboot實現預覽pdf

摘要： 最近，專案上要做個列印的東西，還要預覽。我想就直接生成pdf預覽，然後使用者選擇列印 於是，昨天找了找資料。一般用itext 進行轉pdf。於是我就用springboot試了試，程式碼比較簡單，現在只是簡單的一個實現。 整體流程如下 1.獲取資料（比如從資料庫獲取資料） ...

最近，專案上要做個列印的東西，還要預覽。我想就直接生成pdf預覽，然後使用者選擇列印

於是，昨天找了找資料。一般用itext 進行轉pdf。於是我就用springboot試了試，程式碼比較簡單，現在只是簡單的一個實現。

整體流程如下

• 1.獲取資料（比如從資料庫獲取資料）
• 2.通過freemarker 渲染頁面
• 3.將渲染的頁面進行轉換為pdf，放在本地
• 4.讀取pdf，實現預覽

主要程式碼

pom檔案

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-freemarker</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-web</artifactId>
<version>RELEASE</version>
<scope>compile</scope>
</dependency>

<!-- https://mvnrepository.com/artifact/com.itextpdf/itextpdf -->
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>itextpdf</artifactId>
<version>5.5.13</version>
</dependency>

<!-- https://mvnrepository.com/artifact/com.itextpdf.tool/xmlworker -->
<dependency>
<groupId>com.itextpdf.tool</groupId>
<artifactId>xmlworker</artifactId>
<version>5.5.13</version>
</dependency>


<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.5</version>
</dependency>
</dependencies>

PdfController程式碼

package com.kevin.pdf_demo.controller;

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.PdfWriter;
import com.itextpdf.tool.xml.XMLWorkerFontProvider;
import com.itextpdf.tool.xml.XMLWorkerHelper;
import freemarker.template.Configuration;
import freemarker.template.Template;
import org.apache.commons.io.IOUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.ClassPathResource;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.Map;

/**
 * @author: kevin
 * @Date: 2018/11/16
 */
@RestController
public class PdfController {
@Value("${DEST}")
private String dest;
@Value("${HTML}")
private String html;
@Value("${FONT}")
private String font;
private static Configuration freemarkerCfg = null;


@RequestMapping(value = "helloPdf")
public void showPdf(HttpServletResponse response) throws IOException, DocumentException {
//需要填充的資料
Map<String, Object> data = new HashMap<>(16);
data.put("name", "kevin");

String content = freeMarkerRender(data,html);
//建立pdf
createPdf(content, dest);

// 讀取pdf並預覽
readPdf(response);

}

publicvoid createPdf(String content,String dest) throws IOException, DocumentException {
// step 1
Document document = new Document();
// step 2
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(dest));
// step 3
document.open();
// step 4
XMLWorkerFontProvider fontImp = new XMLWorkerFontProvider(XMLWorkerFontProvider.DONTLOOKFORFONTS);
fontImp.register(font);
XMLWorkerHelper.getInstance().parseXHtml(writer, document,
new ByteArrayInputStream(content.getBytes("UTF-8")), null, Charset.forName("UTF-8"), fontImp);
// step 5
document.close();

}

/**
* freemarker渲染html
*/
publicString freeMarkerRender(Map<String, Object> data, String htmlTmp) {
Writer out = new StringWriter();

try {
// 獲取模板,並設定編碼方式
setFreemarkerCfg();
Template template = freemarkerCfg.getTemplate(htmlTmp);
template.setEncoding("UTF-8");
//將合併後的資料和模板寫入到流中，這裡使用的字元流
template.process(data, out);
out.flush();
return out.toString();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
out.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
return null;
}
/**
* 設定freemarkerCfg
*/
private void setFreemarkerCfg() {
freemarkerCfg = new Configuration();
//freemarker的模板目錄
try {
freemarkerCfg.setDirectoryForTemplateLoading(new ClassPathResource("template").getFile());
} catch (IOException e) {
e.printStackTrace();
}
}

/**
* 讀取本地pdf,這裡設定的是預覽
*/
private void readPdf(HttpServletResponse response) {
response.reset();
response.setContentType("application/pdf");
try {
File file = new File(dest);
FileInputStream fileInputStream = new FileInputStream(file);
OutputStream outputStream = response.getOutputStream();
IOUtils.write(IOUtils.toByteArray(fileInputStream), outputStream);
response.setHeader("Content-Disposition",
"inline; filename= file");
outputStream.flush();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}



}

執行效果

設定頭資訊使瀏覽器下載檔案或預覽

強制瀏覽器下載

response.setHeader("content-disposition", "attachment;filename=" + realName);

瀏覽器嘗試開啟,支援office online或瀏覽器預覽pdf功能

response.setHeader("content-disposition", "inline;filename=" + realName);

完整程式碼 : SpringBoot" rel="nofollow,noindex" target="_blank">github

玩的開心！