first commit

src/main/java/com/peanut/common/utils/FileDownloadUtil.java

@@ -0,0 +1,71 @@
+package com.peanut.common.utils;
+
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
+import java.net.URL;
+
+public class FileDownloadUtil {
+
+    /**
+     * @return
+     * @description: 从服务器获得一个输入流
+     */
+    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();
+            System.out.println("responseCode is:" + responseCode);
+            if (responseCode == HttpURLConnection.HTTP_OK) {
+                // 从服务器返回一个输入流
+                inputStream = httpURLConnection.getInputStream();
+            } else {
+                inputStream = httpURLConnection.getErrorStream();
+            }
+        } catch (MalformedURLException e) {
+            e.printStackTrace();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return inputStream;
+    }
+
+    /**
+     * @param resp
+     * @param inputStream
+     * @description: 将输入流输出到页面
+     */
+    public static void writeFile(HttpServletResponse resp, InputStream inputStream) {
+        OutputStream out = null;
+        try {
+            out = resp.getOutputStream();
+            int len = 0;
+            byte[] b = new byte[1024];
+            while ((len = inputStream.read(b)) != -1) {
+                out.write(b, 0, len);
+            }
+            out.flush();
+        } catch (IOException e) {
+            e.printStackTrace();
+        } finally {
+            try {
+                if (out != null) {
+                    out.close();
+                }
+            } catch (Exception e) {
+                e.printStackTrace();
+            }
+        }
+    }
+}