[Android] HTML parser を試す

簡単にHTMLをパースしたい時は、やはりその手のライブラリーを使った方が早いでしょう。Jsoupというのがあります、Android Studio にライブラリーを導入する方法も含めて使い方をのぞいてみます。

Android Studio
2021.2.1

Jsoup HTML parser

build.gradle のdependenciesに記述します。バージョンはjsoup.org のサイトで見てください。
　
build.gradle

dependencies {
    ...
    implementation 'org.jsoup:jsoup:1.13.1'
}

dependencies {

...

implementation 'org.jsoup:jsoup:1.13.1'

}

　
あるいはjsoup.org のサイトhttp://jsoup.org/からjarフィルをダウンロードすることも可能です。
　
jsoup-x.x.x.jar （バージョンは随時変わります）を..¥app¥libs 以下に保存　(Expoloreなどで入る)
　
「File」「Project Structure…」から
「app」のタグ「Dependencies」を選びダウンロードしたjarファイルを選択する
　

jsoup の cookbook に沿って簡単なアプリを作ってみると
　
MainActivity.java

//package your.package.name;

/*
Copyright © 2009 - 2016 Jonathan Hedley (jonathan@hedley.net)

Permission is hereby granted, free of charge, to any person obtaining a copy of 
this software and associated documentation files (the "Software"), to deal 
in the Software without restriction, including without limitation the rights to use, 
copy, modify, merge, publish, distribute, sublicense, and/or sell copies of 
the Software, and to permit persons to whom the Software is furnished to do so, 
subject to the following conditions:
The above copyright notice and this permission notice shall be included in 
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR 
THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.select.Elements;

public class MainActivity extends AppCompatActivity {

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

        String html = "<html><head><title>First parse</title></head>"
                + "<body><p>Parsed HTML into a doc.</p></body></html>";

        Document doc = Jsoup.parse(html);

        Elements title = doc.select("title");
        Log.d("debug", "doc= " + doc);
        Log.d("debug", "title= " + title);
    }
}

//package your.package.name;

Permission is hereby granted, free of charge, to any person obtaining a copy of

this software and associated documentation files (the "Software"), to deal

in the Software without restriction, including without limitation the rights to use,

copy, modify, merge, publish, distribute, sublicense, and/or sell copies of

the Software, and to permit persons to whom the Software is furnished to do so,

subject to the following conditions:

The above copyright notice and this permission notice shall be included in

all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,

ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR

THE USE OR OTHER DEALINGS IN THE SOFTWARE.

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.util.Log;

import org.jsoup.Jsoup;

import org.jsoup.nodes.Document;

import org.jsoup.select.Elements;

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

String html = "<html><head><title>First parse</title></head>"

+ "<body><p>Parsed HTML into a doc.</p></body></html>";

Document doc = Jsoup.parse(html);

Elements title = doc.select("title");

Log.d("debug", "doc= " + doc);

Log.d("debug", "title= " + title);

}

　
Logが出力されました
　

07-05 02:35:59.250  12233-12233/com.example.testhtmlparser D/﹕ doc= <html>
    <head>
    <title>First parse</title>
    </head>
    <body>
    <p>Parsed HTML into a doc.</p>
    </body>
    </html>
07-05 02:35:59.250  12233-12233/com.example.testhtmlparser D/﹕ title= <title>First parse</title>

07-05 02:35:59.250 12233-12233/com.example.testhtmlparser D/﹕ doc= <html>

<head>

<title>First parse</title>

</head>

<body>

<p>Parsed HTML into a doc.</p>

</body>

</html>

07-05 02:35:59.250 12233-12233/com.example.testhtmlparser D/﹕ title= <title>First parse</title>

　
確かに html ファイルのタイトルを取り出しています
　
ネット上のhtmlをパースして情報を取り出すには、非同期で行う必要があります。
　
　
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