Java从服务器获得图片输入流InputStream,并写到本地磁盘

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Java从服务器获得图片输入流InputStream,并写到本地磁盘

1、创建测试类（HttpUtils.java）

package com.jeff.utils;import java.io.IOException;
import java.io.InputStream;
import java.HttpURLConnection;
import java.MalformedURLException;
import java.URL;public class HttpUtils {/*** * @description: 从服务器获得一个输入流(本例是指从服务器获得一个image输入流)* @author: Jeff* @date: 2019年12月7日* @return*/public static InputStream getInputStream(String urlPath) {InputStream inputStream = null;HttpURLConnection httpURLConnection = null;try {URL url = new URL(urlPath);httpURLConnection = (HttpURLConnection) url.openConnection();// 设置网络连接超时时间httpURLConnection.setConnectTimeout(3000);// 设置应用程序要从网络连接读取数据httpURLConnection.setDoInput(true);httpURLConnection.setRequestMethod("GET");int responseCode = httpURLConnection.getResponseCode();if (responseCode == 200) {// 从服务器返回一个输入流inputStream = httpURLConnection.getInputStream();}} catch (MalformedURLException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}return inputStream;}public static void main(String args[]) {// 服务器图片urlString urlPath = "http://192.168.1.100:8080/images/jie.jpg";// 本地文件夹路径String diskPath = "F:\\Jeff\\images\\";// 从服务器端获得图片，并保存到本地FileUtils.saveImageToDisk(getInputStream(urlPath), diskPath);}}

2、创建文件流工具类（FileUtils.java）

package com.jeff.utils;import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;public class FileUtils {public static final String TYPE_JPG = "jpg";public static final String TYPE_GIF = "gif";public static final String TYPE_PNG = "png";public static final String TYPE_BMP = "bmp";public static final String TYPE_UNKNOWN = "unknown";public static final String FORMAT_FILE_NAME = "%d.%s";private static byte[] b;/*** * @description: 根据文件流判断图片类型* @author: Jeff* @date: 2019年12月7日* @param fis 文件输入流* @return*/public static String getPicType(InputStream fis) {// 读取文件的前几个字节来判断图片格式b = new byte[4];try {fis.read(b, 0, b.length);String type = bytesToHexString(b).toUpperCase();if (type.contains("FFD8FF")) {return TYPE_JPG;} else if (type.contains("89504E47")) {return TYPE_PNG;} else if (type.contains("47494638")) {return TYPE_GIF;} else if (type.contains("424D")) {return TYPE_BMP;} else {return TYPE_UNKNOWN;}} catch (IOException e) {e.printStackTrace();}return null;}/*** * @description: byte数组转换成16进制字符串* @author: Jeff* @date: 2019年12月7日* @param src* @return*/public static String bytesToHexString(byte[] src) {StringBuilder stringBuilder = new StringBuilder();if (src == null || src.length <= 0) {return null;}for (int i = 0; i < src.length; i++) {int v = src[i] & 0xFF;String hv = Integer.toHexString(v);if (hv.length() < 2) {stringBuilder.append(0);}stringBuilder.append(hv);}return stringBuilder.toString();}/*** * @description: 判断文件夹是否存在，不存在则创建* @author: Jeff* @date: 2019年12月7日* @param dir*/public static void isDirPathExist(File dir) {// 判断文件夹是否存在if (dir.isDirectory()) {System.out.println(dir + "文件夹已存在");} else {System.out.println(dir + "文件夹不存在");dir.mkdir();System.out.println("创建文件夹" + dir);}}/*** * @description: 从服务器获得图片输入流InputStream,并写到本地磁盘* @author: Jeff* @date: 2019年12月7日*/public static void saveImageToDisk(InputStream inputStream, String diskPath) {// 根据文件流判断图片类型，此处不要关闭流,要不然下方获取不到输入流String picType = FileUtils.getPicType(inputStream);System.out.println("图片格式为：" + picType);String fileName = String.format(FORMAT_FILE_NAME, new Date().getTime(), picType);System.out.println("图片名字为：" + fileName);byte[] data = new byte[1024];int len = 0;FileOutputStream fileOutputStream = null;try {File dirFile = new File(diskPath);// 判断文件夹是否存在，不存在则创建FileUtils.isDirPathExist(dirFile);fileOutputStream = new FileOutputStream(new File(dirFile, fileName));// 首先写入判断图片格式的前几个字节fileOutputStream.write(b, 0, b.length);while ((len = inputStream.read(data)) != -1) {fileOutputStream.write(data, 0, len);}fileOutputStream.flush();} catch (IOException e) {e.printStackTrace();} finally {if (inputStream != null) {try {inputStream.close();} catch (IOException e) {e.printStackTrace();}}if (fileOutputStream != null) {try {fileOutputStream.close();} catch (IOException e) {e.printStackTrace();}}}System.out.println(fileName + "写到本地磁盘完成");}}

3、控制台输出结果

4、本地磁盘结果