Android Studioでjdbcを用いてデータベース接続をしたい

androidstudioでjdbcを用いてデータベース接続をしたい

androidstudio(java)でmysqlのデータベースと接続してデータを取得，更新したのですがエラーが出てしまいました．

発生している問題・エラーメッセージ

W/System.err: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: 
    ** BEGIN NESTED EXCEPTION ** 
    java.net.ConnectException
W/System.err: MESSAGE: failed to connect to /xxx.xxx.xxx.xxx(port 3306) from /:: (port 43375): connect failed: ETIMEDOUT (Connection timed out)
    STACKTRACE:
    java.net.ConnectException: failed to connect to /157.112.147.201 (port 3306) from /:: (port 43375): connect failed: ETIMEDOUT (Connection timed out)
        at libcore.io.IoBridge.connect(IoBridge.java:138)
        at java.net.PlainSocketImpl.socketConnect(PlainSocketImpl.java:129)
        at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:356)
W/System.err:     at java.net.Socket.<init>(Socket.java:445)
        at java.net.Socket.<init>(Socket.java:248)
        at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256)
        at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271)
        at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771)
        at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
W/System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
        at java.lang.Thread.run(Thread.java:764)
    Caused by: android.system.ErrnoException: connect failed: ETIMEDOUT (Connection timed out)
        at libcore.io.Linux.connect(Native Method)
        at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:126)
W/System.err: ** END NESTED EXCEPTION **
I/chatty: uid=10202(u0_a202) AsyncTask #4 identical 1 line
W/System.err: Last packet sent to the server was 7 ms ago.
        at com.mysql.jdbc.Connection.createNewIO(Connection.java:2847)
W/System.err:     at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
        at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
        at java.sql.DriverManager.getConnection(DriverManager.java:569)
W/System.err:     at com.example.nfc_checker.MainActivity$DbReload.doInBackground(MainActivity.java:199)
        at com.example.nfc_checker.MainActivity$DbReload.doInBackground(MainActivity.java:166)
        at android.os.AsyncTask$2.call(AsyncTask.java:333)
W/System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)  
W/System.err:     at java.lang.Thread.run(Thread.java:764)

該当のソースコード

java
1import...
2public class MainActivity extends AppCompatActivity {
3    @Override
4    protected void onCreate(Bundle savedInstanceState) {
5        super.onCreate(savedInstanceState);
6        setContentView(R.layout.activity_main);
7        Spinner spinner1 = (Spinner) findViewById(R.id.spinner1);
8        String[] labels = getResources().getStringArray(R.array.spinner_items);
9        ArrayAdapter<String> adapter
10                = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, labels);
11        spinner1.setAdapter(adapter);
12        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
13        Intent intent = getIntent();
14        String action = intent.getAction();
15        if (action.equals((NfcAdapter.ACTION_NDEF_DISCOVERED))) {
16            String item_Id = getItemId(getIntent());
17            if(item_Id != null) {
18                TextView textView4 = (TextView) findViewById(R.id.textView4);
19                textView4.setText(item_Id);
20                DbReload task1 = new DbReload(MainActivity.this);
21                task1.execute();
22            }
23        }
24    }
25    public void onButton1(View view) {
26        try{
27            Class.forName("android.os.AsyncTask");
28        }catch(ClassNotFoundException e){}
29        DbGet task = new DbGet(MainActivity.this);
30        task.execute();
31    }
32    private String getItemId(Intent intent) {
33        //Ndefメッセージの取得
34        Parcelable[] raws = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
35        NdefMessage[] msgs = new NdefMessage[raws.length];
36        String str = "";
37        for (int i = 0; i < raws.length; i++) {
38            msgs[i] = (NdefMessage) raws[i];
39            for (NdefRecord record : msgs[i].getRecords()) {
40                //payloadを取得
41                byte[] payload = record.getPayload();
42                //payloadが空白ならブレイク
43                if (payload == null) break;
44                int idx = 0;
45                for (byte data : payload) {
46                    if (idx > 2) {
47                        str += String.format("%c", data);
48                    }
49                    idx++;
50                }
51            }
52        }
53        return str;
54    }
55
56    public String roomGet() {
57        Spinner spinner1 = (Spinner) findViewById(R.id.spinner1);
58        String room = spinner1.getSelectedItem().toString();
59        return room;
60    }
61  
62    class DbGet extends AsyncTask<Void, Void, String>{
63        Activity activity = null;
64        public DbGet(Activity act) {
65            activity = act;
66        }
67        String driverName = "com.mysql.jdbc.Driver"; 
68        String jdbcUrl = "jdbc:mysql://xxx.xxx.xxx.xxx:3306/nfccheck?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC";
69        String userId = "nfccheck_admin";    
70        String userPass = "asdfasdf"; 
71        Connection con = null;
72        Statement stmt = null;
73        ResultSet rs = null;
74
75        @Override
76        protected String doInBackground(Void... params) {
77            String text1 = "";
78            String room_id = roomGet();
79            System.out.println(room_id);
80
81            try {     
82                try {
83                    Class.forName(driverName);
84                } catch (ClassNotFoundException e) {
85                    e.printStackTrace();
86                    //System.out.println("bbb");
87                }
88
89                con = DriverManager.getConnection( jdbcUrl, userId , userPass);   
90                stmt = con.createStatement();
91                //String sql ="Select * from items WHERE item_room = '" +room_id +"';";
92                String sql = "Select * from items WHERE item_room = 'T001';";
93                rs = stmt.executeQuery(sql);
94
95                while (rs.next()) {
96                    int id = rs.getInt(1);
97                    String item_name = rs.getString(3);
98                    String time = rs.getString(5);
99                    text1 += id + " " + item_name + " " + time + " " + "\r\n";
100                }
101                rs.close();
102                stmt.close();
103                con.close();
104
105            } catch (SQLException e) {
106                text1 = e.getMessage();
107                e.printStackTrace();
108            }
109            return text1;
110        }
111        protected void onPostExecute(String result) {
112            TextView tv = (TextView) activity.findViewById(R.id.textView10);
113            tv.setText(result);
114        }
115    }  
116
117    
118    class DbReload extends AsyncTask<Void, Void, String>{
119        Activity activity = null;
120        public DbReload(Activity act) {
121            activity = act;
122        }
123        String driverName = "com.mysql.jdbc.Driver"; 
124        String jdbcUrl = "jdbc:mysql://xxx.xxx.xxx.xxx:3306/nfccheck?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC";//jdbcのurl
125        String userId = "nfccheck_admin";   
126        String userPass = "asdfasdf";   
127        Connection con = null;
128        Statement stmt = null;
129        ResultSet rs = null;
130
131        @Override
132        protected String doInBackground(Void... params) {
133            String text1 = "";
134            String item_Id = getItemId(getIntent());
135            System.out.println(item_Id);
136
137            //System.out.println("aaaa");
138
139            try {
140                try {
141                    Class.forName(driverName);
142                } catch (ClassNotFoundException e) {
143                    e.printStackTrace();
144                    //System.out.println("bbb");
145                }
146                con = DriverManager.getConnection( jdbcUrl, userId , userPass);
147                stmt = con.createStatement();
148                SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
149                String sql = "UPDATE items SET Up_date = "+dateFormat+"WHERE item_id = '"+item_Id+"';";
150                stmt.executeQuery(sql);
151                sql = "Select item_name from items WHERE item_id = '"+item_Id+"';";
152                rs = stmt.executeQuery(sql);
153
154                while (rs.next()) {
155                    int id = rs.getInt(1);
156                    String item_name = rs.getString(3);
157                    String time = rs.getString(5);
158                    text1 += id + " " + item_name + " " + time + " " + "\r\n";
159                }
160                rs.close();
161                stmt.close();
162                con.close();
163
164            } catch (SQLException e) {
165                text1 = e.getMessage();
166                e.printStackTrace();
167            }
168            return text1;
169        }
170
171        protected void onPostExecute(String result) {
172            TextView tv = (TextView) activity.findViewById(R.id.textView4);
173            tv.setText(result);
174        }
175    }   
176}
177