java+pgsql实现保存图片到数据库，以及读取数据库存储的图片；java将图片保存到本地、保存到数据库、java将图片保存到本地并保存到数据库、java从数据库postgresql读取图片

缺乏、安全感 2022-12-21 00:47 369阅读 0赞

# java将图片保存到本地； #

pom.xml

<dependency>
    			<groupId>cn.hutool</groupId>
    			<artifactId>hutool-all</artifactId>
    			<version>5.4.7</version>
    </dependency>
    <dependency>
    			<groupId>org.apache.httpcomponents</groupId>
    			<artifactId>httpclient</artifactId>
    </dependency>

# java类-将图片直接保存到本地 #

# java类-将图片直接保存到数据库 #

HttpResponse maiImg = HttpRequest.get("http://image.nmc.cn/assets/img/w/40x40/3/0.png").execute();
    InputStream maiImgInpuStream = maiImg.bodyStream(); //图片转换成流
    
    jdbc往数据库汇总插入数据
    //pstmt.setString(2, mai.getFileName());
    //pstmt.setString(3, mai.getUrl());
    pstmt.setBinaryStream(4, maiImgInpuStream, maiImgInpuStream.available());

# java类将图片下载到本地，并将图片保存到数据库 #

逻辑：运用方法一，把图片下载到本地，在从本地读取图片为流的格式，然后把图片保存到数据库

String fileUrl = "http://image.nmc.cn/assets/img/w/40x40/3/0.png";
    
    //将文件下载后保存在E盘，返回结果为下载文件大小
    long size = HttpUtil.downloadFile(fileUrl, FileUtil.file("e:/"));
    System.out.println("Download size: " + size);
            
            try {
    			FileInputStream fis = new FileInputStream(new File("e://3.png"));
    		} catch (FileNotFoundException e1) {
    			// TODO Auto-generated catch block
    			e1.printStackTrace();
    		}
    
    //jdbc插入数据
    pstmt.setBinaryStream(3,fis,fis.avaliable())

# java类从数据库中读取图片 #

// 读取数据库中图片
         public static void readDBImage() {
             String targetPath = "D:/image/1.png";
             Connection conn = null;
             PreparedStatement ps = null;
             ResultSet rs = null;
             try {
                 conn = JdbcUtil.getConn();
                 String sql = "select * from photo where id =?";
                 ps = conn.prepareStatement(sql);
                 ps.setInt(1,1);
                 rs = ps.executeQuery();
                 while (rs.next()) {
                     InputStream in = rs.getBinaryStream("photo");
                     ImageUtil.readBinImage(in, targetPath);
                 }
             } catch (Exception e) {
                 e.printStackTrace();
             } finally {
                 DBUtil.closeConn(conn);
                 if (rs != null) {
                     try {
                         rs.close();
                     } catch (SQLException e) {
                         e.printStackTrace();
                     }
                 }
                 if (ps != null) {
                     try {
                         ps.close();
                     } catch (SQLException e) {
                         e.printStackTrace();
                     }
                 }
     
             }
         }
    
    
    
    public class ImageUtil {
    	// 读取本地图片获取输入流
        public static FileInputStream readImage(String path) throws IOException {
            return new FileInputStream(new File(path));
        }
    
        // 读取表中图片获取输出流
        public static void readBinImage(InputStream in, String targetPath) {
            File file = new File(targetPath);
            String path = targetPath.substring(0, targetPath.lastIndexOf("/"));
            if (!file.exists()) {
                new File(path).mkdir();
            }
            FileOutputStream fos = null;
            try {
                fos = new FileOutputStream(file);
                int len = 0;
                byte[] buf = new byte[1024];
                while ((len = in.read(buf)) != -1) {
                    fos.write(buf, 0, len);
                }
               fos.flush();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (null != fos) {
                    try {
                        fos.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }