java使用hutool把服务器图片链接转为base64编码

系统管理员 2024-04-01 13:09 29阅读 0赞

需求是把服务器的图片链接或者网上的图片链接地址转为base64位编码方便前端操作

## **建议使用方法一** ##

base64编码转为图片在线网址  
[https://imgtobase64.d777.com/][https_imgtobase64.d777.com]

### 方法一：使用hutool的HttpResponse方法 ###

#### 1.1 引入依赖 ####

<dependency>
       <groupId>cn.hutool</groupId>
        <artifactId>hutool-all</artifactId>
        <version>5.7.22</version>
    </dependency>

#### 1.2 代码 ####

import cn.hutool.http.HttpRequest;
    import cn.hutool.http.HttpResponse;
    import sun.misc.BASE64Encoder;
    
    import java.io.ByteArrayOutputStream;
    import java.io.InputStream;
    import java.util.regex.Matcher;
    import java.util.regex.Pattern;
    
    /**
     * @Author ekkcole
     * @remark 图片链接转为base64编码
     */
    public class UrlToBase64Util {
        
    	
    	//base64前缀
    	private static final String BASE64_PREFIX="data:image/png;base64,";
    
    	public static void main(String[] args) throws Exception {
        
    		String url="https://localhost:8080/upload/file/20221101/test.png";
    		System.out.println(BASE64_PREFIX+imageUrlToBase64(url));
    	}
    
    	/**
    	 * 图片URL转Base64编码
    	 *
    	 * @param imgUrl 图片URL
    	 * @return Base64编码
    	 */
    	public static String imageUrlToBase64(String imgUrl) {
        
    		InputStream is = null;
    		ByteArrayOutputStream outStream = null;
    		try {
        
    			if (!ObjectUtils.isEmpty(imgUrl)) {
        
    				HttpResponse res = HttpRequest.get(imgUrl).execute();
    				// 获取输入流
    				is = res.bodyStream();
    				outStream = new ByteArrayOutputStream();
    				//创建一个Buffer字符串
    				byte[] buffer = new byte[1024];
    				//每次读取的字符串长度，如果为-1，代表全部读取完毕
    				int len = 0;
    				//使用输入流从buffer里把数据读取出来
    				while ((len = is.read(buffer)) != -1) {
        
    					//用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度
    					outStream.write(buffer, 0, len);
    				}
    				// 对字节数组Base64编码
    				return encode(outStream.toByteArray());
    			}
    		} catch (Exception e) {
        
    			e.printStackTrace();
    		} finally {
        
    			try {
        
    				if (is != null) {
        
    					is.close();
    				}
    				if (outStream != null) {
        
    					outStream.close();
    				}
    			} catch (Exception e) {
        
    				e.printStackTrace();
    			}
    		}
    		return null;
    	}
    
    	/**
    	 * 图片转字符串
    	 *
    	 * @param image 图片Buffer
    	 * @return Base64编码
    	 */
    	public static String encode(byte[] image) {
        
    		BASE64Encoder decoder = new BASE64Encoder();
    		return replaceEnter(decoder.encode(image));
    	}
    
    	/**
    	 * 字符替换
    	 *
    	 * @param str 字符串
    	 * @return 替换后的字符串
    	 */
    	public static String replaceEnter(String str) {
        
    		String reg = "[\n-\r]";
    		Pattern p = Pattern.compile(reg);
    		Matcher m = p.matcher(str);
    		return m.replaceAll("");
    	}
    }

### 方法二：使用自带的请求，有的网址会报错，建议用第一种 ###

import org.springframework.util.ObjectUtils;
    import sun.misc.BASE64Encoder;
    
    import java.io.*;
    import java.net.HttpURLConnection;
    import java.net.URL;
    import java.util.regex.Matcher;
    import java.util.regex.Pattern;
    
    public class UrlToBase64 {
        
    
    	//base64前缀
    	private static final String BASE64_PREFIX="data:image/png;base64,";
    
    	public static void main(String[] args) throws Exception {
        
    		String url="https://localhost:8080/upload/file/20221101/test.png";
    		System.out.println(BASE64_PREFIX+imageUrlToBase64(url));
    	}
    
        /**
         * 图片URL转Base64编码
         * @param imgUrl 图片URL
         * @return Base64编码
         */
        public static String imageUrlToBase64(String imgUrl) {
        
            URL url = null;
            InputStream is = null;
            ByteArrayOutputStream outStream = null;
            HttpURLConnection httpUrl = null;
    
            try {
        
    			if (!ObjectUtils.isEmpty(imgUrl)) {
        
    				// 如果服务器图片地址带有中文，最好处理一下
    				String[] argss = imgUrl.split("/");
    				String name1 = argss[argss.length - 1];
    				String name2 = java.net.URLEncoder.encode(name1, "utf-8");
    				// 处理中文名
    				String newUrl = imgUrl.replace(name1, name2);
    				url = new URL(newUrl);
    				httpUrl = (HttpURLConnection) url.openConnection();
    				httpUrl.connect();
    				httpUrl.getInputStream();
    
    				is = httpUrl.getInputStream();
    				outStream = new ByteArrayOutputStream();
    
    				//创建一个Buffer字符串
    				byte[] buffer = new byte[1024];
    				//每次读取的字符串长度，如果为-1，代表全部读取完毕
    				int len = 0;
    				//使用输入流从buffer里把数据读取出来
    				while ((len = is.read(buffer)) != -1) {
        
    					//用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度
    					outStream.write(buffer, 0, len);
    				}
    				// 对字节数组Base64编码
    				return encode(outStream.toByteArray());
    			}
            } catch (Exception e) {
        
                e.printStackTrace();
            } finally {
        
                try {
        
                    if(is != null) {
        
                        is.close();
                    }
                    if(outStream != null) {
        
                        outStream.close();
                    }
                    if(httpUrl != null) {
        
                        httpUrl.disconnect();
                    }
                } catch (Exception e) {
        
                    e.printStackTrace();
                }
            }
    
            return null;
        }
    
        /**
         * 图片转字符串
         * @param image 图片Buffer
         * @return Base64编码
         */
        public static String encode(byte[] image){
        
            BASE64Encoder decoder = new BASE64Encoder();
            return replaceEnter(decoder.encode(image));
        }
    
        /**
         * 字符替换
         * @param str 字符串
         * @return 替换后的字符串
         */
        public static String replaceEnter(String str){
        
            String reg ="[\n-\r]";
            Pattern p = Pattern.compile(reg);
            Matcher m = p.matcher(str);
            return m.replaceAll("");
        }
    
    
    }

[https_imgtobase64.d777.com]: https://imgtobase64.d777.com/