安卓开发获取网页源码

new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    java.net.URL urlInfo = new URL("https://xlj0.com");

                    // 开启请求
                    HttpURLConnection httpConnect = (HttpURLConnection) urlInfo.openConnection();
                    // 设置加载方式
                    httpConnect.setRequestMethod("POST");
                    // 设置是否从 HttpURLConnection 读入
                    httpConnect.setDoInput(true);
                    // 设置是否从 HttpURLConnection 读出
                    httpConnect.setDoOutput(true);
                    // 设置连接超时时间 - 单位: ms
                    httpConnect.setConnectTimeout(2 * 2500);
                    // 设置读取超时时间 - 单位: ms
                    httpConnect.setReadTimeout(2 * 2500);
                    // 开启连接
                    httpConnect.connect();

                    // 执行结果状态码
                    int httpCode = httpConnect.getResponseCode();
                    Log.i("Info", "状态:" + httpCode);

                    // 得到结果
                    if (httpConnect.getResponseCode() == 200) {
                        Log.i("Info", "获取成功 内容长度:" + httpConnect.getContentLength());

                        // 创建字节流组
                        InputStream inputStream = httpConnect.getInputStream();
                        // 创建字节流组输出流
                        ByteArrayOutputStream ziJieLiuZuShuChuLiu = new ByteArrayOutputStream();
                        // 创建缓存
                        byte[] buffer = new byte[2048];
                        // 创建行数
                        int outLength = -1;
                        // 循环读出
                        while ((outLength = inputStream.read(buffer)) != -1) {
                            // 读出数据
                            ziJieLiuZuShuChuLiu.write(buffer, 0, outLength);
                        }

                        // 字节流数据转化成字符串 - 数据获取完成
                        String shuJu = ziJieLiuZuShuChuLiu.toString();

                        // 打印数据
                        Log.i("inputStream", "内容:" + shuJu);


                        httpConnect.disconnect();
                    } else {
                        Log.i("Info", String.valueOf(httpConnect.getContentLength()));

                        // 发送数据
                        Message message = new Message();
                        message.what = ERROR;
                        hander.sendMessage(message);

                        httpConnect.disconnect();
                    }

                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
}).start();

// 逻辑变量
    private static final int SUCCESS = 0;
    private static final int ERROR = 1;
    // 创建 Handler 线程
    private Handler hander = new Handler(){
        @Override
        public void handleMessage(@NonNull Message msg) {
            super.handleMessage(msg);
            switch (msg.what) {
                case SUCCESS:
                    Toast.makeText(MainActivity.this, "下载完成", Toast.LENGTH_LONG).show();
                    break;
                case ERROR:
                    Toast.makeText(MainActivity.this, "下载出错", Toast.LENGTH_LONG).show();
                    break;
            }
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // 点击事件
        dianJiShiJian();
    }

    private void dianJiShiJian() {
        // 绑定控件
        final Button xiaZaiWenJian_Button = (Button) findViewById(R.id.xiaZaiWenJian_Button);

        // 下载文件
        xiaZaiWenJian_Button.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view) {
                Toast.makeText(MainActivity.this, "点击成功", Toast.LENGTH_LONG).show();
                XiaZaiWenJian();
            }
        });
    }

    // 开启线程 XiaZaiWenJian - 开线程下载文件
    private void XiaZaiWenJian () {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    java.net.URL urlInfo = new URL("https://xlj0.com");

                    // 开启请求
                    HttpURLConnection httpConnect = (HttpURLConnection) urlInfo.openConnection();
                    // 设置加载方式
                    httpConnect.setRequestMethod("POST");
                    // 设置是否从 HttpURLConnection 读入
                    httpConnect.setDoInput(true);
                    // 设置是否从 HttpURLConnection 读出
                    httpConnect.setDoOutput(true);
                    // 设置连接超时时间 - 单位: ms
                    httpConnect.setConnectTimeout(2 * 2500);
                    // 设置读取超时时间 - 单位: ms
                    httpConnect.setReadTimeout(2 * 2500);
                    // 开启连接
                    httpConnect.connect();

                    // 执行结果状态码
                    int httpCode = httpConnect.getResponseCode();
                    Log.i("Info", "状态:" + httpCode);

                    // 得到结果
                    if (httpConnect.getResponseCode() == 200) {
                        Log.i("Info", "获取成功 内容长度:" + httpConnect.getContentLength());

                        // 创建字节流组
                        InputStream inputStream = httpConnect.getInputStream();
                        // 创建字节流组输出流
                        ByteArrayOutputStream ziJieLiuZuShuChuLiu = new ByteArrayOutputStream();
                        // 创建缓存
                        byte[] buffer = new byte[2048];
                        // 创建行数
                        int outLength = -1;
                        // 循环读出
                        while ((outLength = inputStream.read(buffer)) != -1) {
                            // 读出数据
                            ziJieLiuZuShuChuLiu.write(buffer, 0, outLength);
                        }

                        // 字节流数据转化成字符串
                        String shuJu = ziJieLiuZuShuChuLiu.toString();

                        // 更新UI线程
                        Message message = new Message();
                        message.what = SUCCESS;
                        hander.sendMessage(message);

                        // 打印数据
                        Log.i("inputStream", "内容:" + shuJu);


                        httpConnect.disconnect();
                    } else {
                        Log.i("Info", String.valueOf(httpConnect.getContentLength()));

                        // 发送数据
                        Message message = new Message();
                        message.what = ERROR;
                        hander.sendMessage(message);

                        httpConnect.disconnect();
                    }

                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }
}

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/xiaZaiWenJian_Button"
            android:text="下载文件"/>

    </LinearLayout>

</androidx.constraintlayout.widget.ConstraintLayout>