Merge pull request #1684 from book-ccr/master

#6 #76 第六次实验

students/net1814080903334/NetActivity.java

@@ -0,0 +1,110 @@
+package edu.hzuapps.androidlabs.net1814080903334;
+
+import androidx.appcompat.app.AppCompatActivity;
+
+import android.os.Bundle;
+import android.os.Environment;
+import android.view.View;
+import android.widget.Button;
+import android.widget.EditText;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+import static android.view.View.*;
+
+
+public class NetActivity extends AppCompatActivity {
+
+    private Button download=null;
+    private EditText url=null;
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+
+        this.download=(Button) this.findViewById(R.id.button1);
+        this.url=(EditText) this.findViewById(R.id.editText1);
+
+        this.download.setOnClickListener(new ClickListener());
+    }
+
+    private  final class ClickListener implements OnClickListener
+    {
+        public void onClick(View v)
+        {
+            String httpUrl=url.getText().toString();
+            try
+            {
+                //创建一个URL对象
+                URL url=new URL(httpUrl);
+                //下载数据的方法
+                DownLoad(url);
+            } catch (Exception e) {
+                // TODO Auto-generated catch block
+                e.printStackTrace();
+            }
+        }
+
+
+        public void DownLoad(final URL url)
+        {
+
+            //开启线程下载数据
+                new Thread(new Runnable()
+                        {
+                            public void run()
+                            {
+                                try
+                                {
+                                    Thread.sleep(2000);
+                                    //获取SDCard的路径
+                                    String path=Environment.getExternalStorageDirectory().getAbsolutePath().toString();
+                                    //新建文件
+                                    File file=new File(path+"/Mp3");
+                                    //判段文件是否存在
+                                    if(!file.exists())
+                                    {
+                                        //创建目录
+                                        file.mkdir();
+                                    }
+                                    //创建文件，并起名为a.mp3
+                                    File files=new File(file.getAbsolutePath(),"a.mp3");
+                                    @SuppressWarnings("resource")
+                                    //用来保存读取到的网络数据，保存到文件中
+                                    FileOutputStream  fileoutputstream=new FileOutputStream(files) ;
+                                    //获取httpURLConnection
+                                    HttpURLConnection http=(HttpURLConnection) url.openConnection();
+                                    //设置请求方式
+                                    http.setRequestMethod("GET");
+                                    //设置连接超时时间
+                                    http.setConnectTimeout(5000);
+                                    //如果连接成功读取网络数据
+                                    if(http.getResponseCode()==200)
+                                    {
+                                        //得到HttpURLConnection的输入流对象，用拿来读取网络中的数据
+                                        InputStream inputstream=http.getInputStream();
+                                        //调用WebTools中的getData方法并得到数据
+                                        byte[] data=WebTools.getData(inputstream);
+                                        //把数据写入到文件中
+                                        fileoutputstream.write(data);
+                                        System.out.println("下载成功");
+                                    }
+
+                                }
+                                catch (Exception e)
+                                {
+                                    e.printStackTrace();
+                                }
+                            }
+
+                        }).start();
+
+
+                }
+
+    }
+
+}

students/net1814080903334/WebTools.java

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+package edu.hzuapps.androidlabs.net1814080903334;
+
+import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
+
+public class WebTools {
+
+    public static byte[] getData(InputStream input) throws Exception
+    {
+        //存放数据的byte数组
+        byte[] buffer=new byte[5000];
+        //保存数据的输出流对象
+        ByteArrayOutputStream output=new ByteArrayOutputStream();
+        int len=0;
+        while((len=input.read(buffer))!=-1)
+        {
+            //写入数据
+            output.write(buffer, 0, len);
+        }
+        //返回输入流中的数据
+        return output.toByteArray();
+
+    }
+}