svg转换到base64格式

た入场券 2023-10-02 23:38 7阅读 0赞

## 需求背景 ##

需要将端上传过来的svg文件解析为字符串，然后再生成jpeg格式图片，再将图片转成Base64格式进行使用

## 实现代码 ##

首先引入如下以来。版本一定按照这个来，高版本会出现各种类丢失的问题。

<dependency>
                <groupId>batik</groupId>
                <artifactId>batik-svggen</artifactId>
                <version>1.6</version>
            </dependency>
            <dependency>
                <groupId>batik</groupId>
                <artifactId>batik-awt-util</artifactId>
                <version>1.6</version>
            </dependency>
            <dependency>
                <groupId>batik</groupId>
                <artifactId>batik-bridge</artifactId>
                <version>1.6</version>
            </dependency>
            <dependency>
                <groupId>batik</groupId>
                <artifactId>batik-css</artifactId>
                <version>1.6</version>
            </dependency>
            <dependency>
                <groupId>batik</groupId>
                <artifactId>batik-dom</artifactId>
                <version>1.6</version>
            </dependency>
            <dependency>
                <groupId>batik</groupId>
                <artifactId>batik-gvt</artifactId>
                <version>1.6</version>
            </dependency>
            <dependency>
                <groupId>batik</groupId>
                <artifactId>batik-parser</artifactId>
                <version>1.6</version>
            </dependency>
            <dependency>
                <groupId>batik</groupId>
                <artifactId>batik-script</artifactId>
                <version>1.6</version>
            </dependency>
            <dependency>
                <groupId>batik</groupId>
                <artifactId>batik-svg-dom</artifactId>
                <version>1.6</version>
            </dependency>
            <dependency>
                <groupId>batik</groupId>
                <artifactId>batik-transcoder</artifactId>
                <version>1.6</version>
            </dependency>
            <dependency>
                <groupId>batik</groupId>
                <artifactId>batik-util</artifactId>
                <version>1.6</version>
            </dependency>
            <dependency>
                <groupId>batik</groupId>
                <artifactId>batik-xml</artifactId>
                <version>1.6</version>
            </dependency>
            
            <dependency>
                <groupId>xerces</groupId>
                <artifactId>xercesImpl</artifactId>
                <version>2.9.0</version>
            </dependency>
            <dependency>
                <groupId>org.axsl.org.w3c.dom.svg</groupId>
                <artifactId>svg-dom-java</artifactId>
                <version>1.1</version>
            </dependency>
            <dependency>
                <groupId>org.w3c.css</groupId>
                <artifactId>sac</artifactId>
                <version>1.3</version>
            </dependency>

再就是工具类代码

package com.netease.music.sociallive.game.common.utils;
    
    import com.netease.music.sociallive.game.common.constant.StreamConst;
    import lombok.extern.slf4j.Slf4j;
    import org.apache.batik.transcoder.TranscoderInput;
    import org.apache.batik.transcoder.TranscoderOutput;
    import org.apache.batik.transcoder.image.JPEGTranscoder;
    
    import java.io.BufferedInputStream;
    import java.io.ByteArrayInputStream;
    import java.io.ByteArrayOutputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.nio.charset.StandardCharsets;
    import java.util.Base64;
    
    @Slf4j
    public class SvgImageUtil {
        
    
        private final static int BUF_SIZE = 1024;
        private final static String PREFIX = "data:image/jpeg;base64,";
    
        /**
         * 将svg字符串转为base64
         *
         * @param svgCode  svg字符串
         * @param filePath 临时存储文件的地址
         * @return base64格式表示的jpeg文件
         */
        public static String convertSvgToBase64(String svgCode, String filePath) {
        
            String base64Code = "";
            File file = new File(filePath);
            FileOutputStream outputStream = null;
            try {
        
                file.createNewFile();
                outputStream = new FileOutputStream(file);
                byte[] bytes = svgCode.getBytes(StandardCharsets.UTF_8);
                JPEGTranscoder t = new JPEGTranscoder();
                //压缩图片质量
                t.addTranscodingHint(JPEGTranscoder.KEY_QUALITY, 0.50f);
                TranscoderInput input = new TranscoderInput(new ByteArrayInputStream(bytes));
                TranscoderOutput output = new TranscoderOutput(outputStream);
                t.transcode(input, output);
                //将svg转为jpeg文件暂存在本地磁盘
                outputStream.flush();
    
                //本地jpeg文件读取后转化为base64格式
                base64Code = Base64.getEncoder().encodeToString(toByteArray(filePath));
    
                //删除本地暂存的文件
                File f = new File(filePath);
                if (f.isFile() && f.exists()) {
        
                    f.delete();
                }
            } catch (Exception e) {
        
                log.error("@@图片处理@@ svg转化为base64失败", e);
            } finally {
        
                if (outputStream != null) {
        
                    try {
        
                        outputStream.close();
                    } catch (Exception e) {
        
                        log.error("@@图片处理@@ 关闭io流失败", e);
                    }
                }
            }
            return PREFIX + base64Code;
        }
    
    
        /**
         * 将本地文件读取到字节数组中
         *
         * @param filePath 文件地址
         * @return res
         */
        private static byte[] toByteArray(String filePath) {
        
            File f = new File(filePath);
            if (!f.exists()) {
        
                log.error("@图片处理@@ 未找到本地图片");
                return new byte[0];
            }
            ByteArrayOutputStream bos = new ByteArrayOutputStream((int) f.length());
            BufferedInputStream in = null;
            try {
        
                in = new BufferedInputStream(new FileInputStream(f));
    
                byte[] buffer = new byte[BUF_SIZE];
                int len = StreamConst.NOTHING;
                while (-1 != (len = in.read(buffer, StreamConst.NOTHING, BUF_SIZE))) {
        
                    bos.write(buffer, 0, len);
                }
            } catch (Exception e) {
        
                log.error("@图片处理@@ svg转化为base64失败", e);
            } finally {
        
                try {
        
                    if (in != null) {
        
                        in.close();
                    }
                    bos.close();
                } catch (IOException e) {
        
                    log.error("@@图片处理@@ 关闭io流失败", e);
                }
            }
            return bos.toByteArray();
        }
    
    }

## 功能测试 ##

public static void main(String[] args) {
        
    
            try {
        
                String svgCode = "<svg  height=\"210\" width=\"500\">\n" +
                        "  <polygon points=\"220,10 250,190 160,210\"\n" +
                        "  style=\"fill:lime;stroke:purple;stroke-width:1\"/>\n" +
                        "</svg>";
                System.out.println(convertSvgToBase64(svgCode, "/Users/fps/Desktop/" + Math.random() * 10 + ".jpeg"));
            } catch (Exception e) {
        
                log.error("e", e);
            }
        }

可以看到生成了base64字符串  
![在这里插入图片描述][4641df3e8e0a4249a1423977c9981e40.png]  
进行转化后能够复原出图片  
![在这里插入图片描述][dad345f8811c4caab7909328b2ea09eb.png]

[4641df3e8e0a4249a1423977c9981e40.png]: https://img-blog.csdnimg.cn/4641df3e8e0a4249a1423977c9981e40.png
[dad345f8811c4caab7909328b2ea09eb.png]: https://img-blog.csdnimg.cn/dad345f8811c4caab7909328b2ea09eb.png