用url类来访问服务器上的文件

场景一：

package com.guonian.miaosha;import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;public class Test {public static void main(String[] args) throws IOException {URL url = new URL("http://192.168.1.220:8080/file/%FL%AC%94%E8%BA%.txt");//创建接口地址对象HttpURLConnection connection = (HttpURLConnection)url.openConnection();//设置请求方式//connection.setRequestMethod("GET");connection.connect();BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream(),"UTF-8"));String line = null;while(null != (line = br.readLine())){System.out.println(line);}br.close();}
}

场景2：

public static String image2Base64(String imgUrl, String token) {URL url;InputStream is = null;ByteArrayOutputStream outStream = null;HttpURLConnection httpUrl = null;try {url = new URL(imgUrl);httpUrl = (HttpURLConnection) url.openConnection();httpUrl.setDoOutput(true);httpUrl.setRequestMethod("GET");httpUrl.setRequestProperty("Authorization", token);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;//使用一个输入流从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 CommonUtils.encode(outStream.toByteArray());} catch (Exception e) {log.error("异常信息:", e);} finally {try {if (is != null) {is.close();}if (outStream != null) {outStream.close();}} catch (IOException e) {log.error("异常信息:", e);}if (httpUrl != null) {httpUrl.disconnect();}}return "";}