JAVA后端预览图功能实现

最新推荐文章于 2024-05-13 13:47:19 发布

原创最新推荐文章于 2024-05-13 13:47:19 发布 · 3k 阅读

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文章标签：

#java

该文章介绍了如何通过Java利用Chrome浏览器驱动进行网页截图，处理懒加载页面，将图片流上传至服务器并存储到数据库。涉及的关键技术包括SeleniumWebDriver，Guava库，以及在Linux环境下解决字体问题以避免文字显示为方框。

一、思路

通过浏览器驱动加载页面截图，然后获得图片流，将其上传到图片存储服务器返回图片地址，最后将其存到数据库。

二、浏览器驱动选择

本地测试时，需要根据本地谷歌浏览器版本进行选择

然后去下载浏览器驱动

https://registry.npmmirror.com/binary.html?path=chromedriver/

下载对应系统的驱动包到自己指定的文件目录下，准备工作就完成了。

三、代码实现

依赖准备

<dependency>
    <groupId>org.seleniumhq.selenium</groupId>
    <artifactId>selenium-java</artifactId>
    <version>3.141.59</version>
</dependency>
<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>27.0-jre</version>
</dependency>

import org.openqa.selenium.OutputType;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.chrome.ChromeOptions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.concurrent.TimeUnit;

/**
 * @Version: 1.0
 * @Date: 2023/2/8
 */
public class CutPicture {

private static final Logger LOGGER = LoggerFactory.getLogger(CutPicture.class);

//解决如下： 模拟浏览器滚动滚动条 解决懒加载问题
    public static byte[] guge(String url){
        //这里设置下载的驱动路径，Windows对应chromedriver.exe Linux对应chromedriver，具体路径看你把驱动放在哪
        System.setProperty("webdriver.chrome.driver", "下载的驱动路径");
        ChromeOptions options = new ChromeOptions();
        //ssl证书支持
        options.setCapability("acceptSslCerts", true);
        //截屏支持
        options.setCapability("takesScreenshot", true);
        //css搜索支持
        options.setCapability("cssSelectorsEnabled", true);
        //设置浏览器参数
        options.addArguments("--headless");
        options.addArguments("--no-sandbox");
        options.addArguments("--disable-gpu");
        options.addArguments("--disable-dev-shm-usage");
        options.setHeadless(true);
        ChromeDriver driver = new ChromeDriver(options);
        //设置超时，避免有些内容加载过慢导致截不到图
        driver.manage().timeouts().pageLoadTimeout(1, TimeUnit.MINUTES);
        driver.manage().timeouts().implicitlyWait(1, TimeUnit.MINUTES);
        driver.manage().timeouts().setScriptTimeout(1, TimeUnit.MINUTES);
        try {
            //设置需要访问的地址
            driver.get(url);
            //获取高度和宽度一定要在设置URL之后，不然会导致获取不到页面真实的宽高；
            Long width = (Long)driver.executeScript("return document.documentElement.scrollWidth");
            Long height =(Long) driver.executeScript("return document.documentElement.scrollHeight");
            LOGGER.info("获取截图高度和宽度============================");
            //这里需要模拟滑动，有些是滑动的时候才加在的
            long temp_height = 0;
            while (true) {
                //每次滚动500个像素，因为懒加载所以每次等待2S 具体时间可以根据具体业务场景去设置
                Thread.sleep(2000);
                driver.executeScript("window.scrollBy(0,500)");
                temp_height += 500;
                if(temp_height>=height){
                    break;
                }
            }
            //设置窗口宽高，设置后才能截全
            driver.manage().window().setSize(new org.openqa.selenium.Dimension(width.intValue(), height.intValue()));
            //设置截图文件本地保存的路径，这里我们上传到服务器
//            String screenshotPath = "E:/work/imgGG.png";
            byte[] srcBytes = driver.getScreenshotAs(OutputType.BYTES);
//            FileUtils.copyFile(srcFile, new File(screenshotPath));
            LOGGER.info("截图成功============================");
            return srcBytes;
        }catch (Exception e){
            LOGGER.error("截图失败",e);
        }finally {
            driver.quit();
        }
        return null;

}

然后将byte数组转为文件进行上传，因为项目是用的若依框架，直接用的若依上传方法，但是需要将byte数组转为MultipartFile。

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.ruoyi.web.controller.tool;

import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.FileCopyUtils;
import org.springframework.web.multipart.MultipartFile;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;

public class MockMultipartFile implements MultipartFile {
    private final String name;
    private String originalFilename;
    @Nullable
    private String contentType;
    private final byte[] content;

    public MockMultipartFile(String name, @Nullable byte[] content) {
        this(name, "", (String)null, (byte[])content);
    }

    public MockMultipartFile(String name, InputStream contentStream) throws IOException {
        this(name, "", (String)null, (byte[])FileCopyUtils.copyToByteArray(contentStream));
    }

    public MockMultipartFile(String name, @Nullable String originalFilename, @Nullable String contentType, @Nullable byte[] content) {
        Assert.hasLength(name, "Name must not be null");
        this.name = name;
        this.originalFilename = originalFilename != null ? originalFilename : "";
        this.contentType = contentType;
        this.content = content != null ? content : new byte[0];
    }

    public MockMultipartFile(String name, @Nullable String originalFilename, @Nullable String contentType, InputStream contentStream) throws IOException {
        this(name, originalFilename, contentType, FileCopyUtils.copyToByteArray(contentStream));
    }

    public String getName() {
        return this.name;
    }

    public String getOriginalFilename() {
        return this.originalFilename;
    }

    @Nullable
    public String getContentType() {
        return this.contentType;
    }

    public boolean isEmpty() {
        return this.content.length == 0;
    }

    public long getSize() {
        return (long)this.content.length;
    }

    public byte[] getBytes() throws IOException {
        return this.content;
    }

    public InputStream getInputStream() throws IOException {
        return new ByteArrayInputStream(this.content);
    }

    public void transferTo(File dest) throws IOException, IllegalStateException {
        FileCopyUtils.copy(this.content, dest);
    }
}

本地测试完成之后上服务器

上服务器使用

准备Linux环境安装Chrome浏览器以及依赖

//chrome程序
yum install https://dl.google.com/linux/direct/google-chrome-stable_current_x86_64.rpm
 
//chrome依赖库 
yum install pango.x86_64 libXcomposite.x86_64 libXcursor.x86_64 libXdamage.x86_64 libXext.x86_64 libXi.x86_64 libXtst.x86_64 cups-libs.x86_64 libXScrnSaver.x86_64 libXrandr.x86_64 GConf2.x86_64 alsa-lib.x86_64 atk.x86_64 gtk3.x86_64 -y

同样需要下载linux版本的驱动包放到自己指定的目录下

如果报错如下：

java.lang.IllegalStateException: The driver is not executable: /home/soft/chrome/chromedriver
    at com.google.common.base.Preconditions.checkState(Preconditions.java:588)
    at org.openqa.selenium.remote.service.DriverService.checkExecutable(DriverService.java:150)
    at org.openqa.selenium.remote.service.DriverService.findExecutable(DriverService.java:141)
    at org.openqa.selenium.chrome.ChromeDriverService.access$000(ChromeDriverService.java:35)
    at org.openqa.selenium.chrome.ChromeDriverService$Builder.findDefaultExecutable(ChromeDriverService.java:159)
    at org.openqa.selenium.remote.service.DriverService$Builder.build(DriverService.java:355)
    at org.openqa.selenium.chrome.ChromeDriverService.createDefaultService(ChromeDriverService.java:94)
    at org.openqa.selenium.chrome.ChromeDriver.<init>(ChromeDriver.java:157)
    at com.bmsoft.evidence.service.impl.ArticleServiceImpl.getFilePathByUrl(ArticleServiceImpl.java:734)
    at com.bmsoft.evidence.service.impl.ArticleServiceImpl.screenshot(ArticleServiceImpl.java:287)
    at com.bmsoft.evidence.service.impl.ArticleServiceImpl$FastClassBySpringCGLIB$dafff6e9.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:752)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:295)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691)
    at com.bmsoft.evidence.service.impl.ArticleServiceImpl$EnhancerBySpringCGLIB$52855f88.screenshot(<generated>)
    at com.bmsoft.evidence.service.impl.AsyncServiceImpl.saveWebSiteDetail(AsyncServiceImpl.java:139)
    at com.bmsoft.evidence.service.impl.AsyncServiceImpl.saveWebSite(AsyncServiceImpl.java:124)
    at com.bmsoft.evidence.service.impl.AsyncServiceImpl$FastClassBySpringCGLIB$d0ae7c23.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:752)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
    at org.springframework.aop.interceptor.AsyncExecutionInterceptor.lambda$invoke$0(AsyncExecutionInterceptor.java:115)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

进入驱动所在文件夹后执行以下命令：

chmod a+x chromedriver

还可能报错是你下载的驱动版本不对，去更换一个对应版本的就行。

最后还有可能图片中的文字出现方框的问题：

 通过查询资料发现是因为系统没有中文字体导致的，然后开始安装系统中文字体

yum install ipa-gothic-fonts xorg-x11-fonts-100dpi xorg-x11-fonts-75dpi xorg-x11-utils xorg-x11-fonts-cyrillic xorg-x11-fonts-Type1 xorg-x11-fonts-misc -y

安装上面字体之后 发现还是有些字变方框，这时候我就把Windows上的一些中文字体移到Linux系统中去了，window字体位置自行百度

#1.在/usr/share/fonts目录下创建 chinese目录进行存放中文字体
mkdir -p /usr/share/fonts/chinese/

#2.为刚加入的字体设置缓存使之有效
fc-cache -fv      

#3.查看系统中的字体，是否已包含songti                     
fc-list

到这里就可以完美生成了。

文章参考了https://blog.youkuaiyun.com/Mli_Mi/article/details/116259669?spm=1001.2014.3001.5506

大家可以去关注一波，感谢原作者的分享。