如何解决使用网页抓取、Jsoup 库、Java、Android Studio 仅从网站获取表格的奇数行但是想要表的所有行
网站的 HTML 代码
<table align="center" border="0" cellpadding="1" cellspacing="1" class="tableborder" width="100%">
<tbody>
<tr align="center" class="grideheader">
<td width="5%" height="30">S.No.</td>
<td width="10%">Date</td>
<td width="70%">Title</td>
</tr>
<tr class="griderow1">
<td align="center" height="30">
1</td>
<td align="center" height="23">
19 May 2021</td>
<td align="left">
<a href="https://jntuh.ac.in/uploads/calendars/RevisedAcademiccalendarBTechB.PharmII_IIIYear_II_Semester_MBA_MCA_II_Year_II_Semester_and_Pharm._D_(Regular)_II_III_IV_V_Year_and_Pharm.D(PB)IIYear.pdf" target="_blank">Revised Academic calendar -B. Tech.- B.Pharm. II & III Year - II Semester,MBA-MCA II Year II Semester and Pharm. D (Regular) II,III,IV,V Year and Pharm.D (PB) II Year<img src=https://jntuh.ac.in/images/new_icon_red.gif></a> </td>
</tr>
<tr class="griderow2">
<td align="center" height="30">
2</td>
<td align="center" height="23">
15 May 2021</td>
<td align="left">
<a href="https://jntuh.ac.in/uploads/bulletins/UG_PGProjects.pdf" target="_blank">Information Regarding UG/PG Projects - Regd<img src=https://jntuh.ac.in/images/new_icon_red.gif></a> </td>
</tr>
<tr class="griderow1">
<td align="center" height="30">
3</td>
<td align="center" height="23">
15 May 2021</td>
<td align="left">
<a href="https://jntuh.ac.in/uploads/bulletins/PharmDPhamD(PB)internships.pdf" target="_blank">Information Regarding Internship Details of PharmD/PharmD(PB) - Reg<img src=https://jntuh.ac.in/images/new_icon_red.gif></a> </td>
</tr>
<tr class="griderow2">
<td align="center" height="30">
4</td>
<td align="center" height="23">
12 May 2021</td>
<td align="left">
<a href="https://jntuh.ac.in/uploads/bulletins/Circular1.pdf" target="_blank">JNTUH-Establishment-Imposing the lockdown by the Government of Telangana across the State to contain the spread of COVID-19 Virus-Regarding.<img src=https://jntuh.ac.in/images/new_icon_red.gif></a> </td>
</tr>
我的活动代码(JAVA)
public class ActivityJNTUH_Bulletin extends AppCompatActivity {
private RecyclerView recyclerView;
private JNTUHBulletinAdapter jntuhBulletinAdapter;
private ArrayList<JNTUHBulletinModel> jntuhBulletinModels = new ArrayList<>();
private ProgressBar progressBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_jntuh__bulletin);
progressBar = (ProgressBar) findViewById(R.id.jntuh_bulletin_progress_bar);
recyclerView = (RecyclerView) findViewById(R.id.jntuh_bulletin_recycler_view);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
jntuhBulletinAdapter = new JNTUHBulletinAdapter(jntuhBulletinModels,this);
recyclerView.setAdapter(jntuhBulletinAdapter);
Content content = new Content();
content.execute();
}
private class Content extends AsyncTask<Void,Void,Void> {
@Override
protected void onCancelled() {
super.onCancelled();
}
@Override
protected void onPreExecute() {
super.onPreExecute();
progressBar.setVisibility(View.VISIBLE);
progressBar.startAnimation(AnimationUtils.loadAnimation(ActivityJNTUH_Bulletin.this,android.R.anim.fade_in));
}
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
progressBar.setVisibility(View.GONE);
progressBar.startAnimation(AnimationUtils.loadAnimation(ActivityJNTUH_Bulletin.this,android.R.anim.fade_out));
jntuhBulletinAdapter.notifyDataSetChanged();
}
@Override
protected Void doInBackground(Void... voids) {
try {
String url = "https://jntuh.ac.in/bulletins";
Document doc = Jsoup.connect(url).get();
Element element = doc.select("table.tableborder").first();
for (Element tr : element.select("tr.griderow1")) {
String date = tr
.select("td")
.text();
String bulletin = tr.select("td.griderow1")
.select("a")
.attr("href");
jntuhBulletinModels.add(new JNTUHBulletinModel(date,bulletin));
Log.d("items","date: " + date + "bulletin: " + bulletin);
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
}
我第一次使用网络抓取,我想我不知道如何在 doInBackground() 中运行循环。如果我在 select() 中传递 tr.griderow2,那么我只会得到偶数行。所以我认为要么存在逻辑错误,要么我需要对偶数行再循环一次。 预先感谢您的回答。
解决方法
For 循环中的更改
for (Element tr : element.select("tr[class^=griderow]")) {
String date = tr
.select("td")
.text();
String bulletin = tr
.select("td[class^=griderow]")
.select("a")
.attr("href");
jntuhBulletinModels.add(new JNTUHBulletinModel(date,bulletin));
Log.d("items","date: " + date + "bulletin: " + bulletin);
}
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