android连数据库

package com.rockcheck.mes;

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

import java.sql.*;

public class PDAActivity extends AppCompatActivity {

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

    //查询oracle数据库
    public void KunHaoQuery(View view) {

        new QueryOracle().execute();
    }

    class QueryOracle extends AsyncTask<Void, Integer, String> {
        String result = null;

        @Override
        protected String doInBackground(Void... voids) {
            result = Query();
            return result;
        }

        @Override
        protected void onPostExecute(String str) {
            Toast.makeText(PDAActivity.this, result, Toast.LENGTH_SHORT).show();
        }
    }

    public String Query() {
        String wuliao = "123";
        String user = "MES";
        String password = "zidonghua";
        String url = "jdbc:oracle:thin:@10.0.2.2:1521:orcl";
        String sql = "select AMOUNT from FRUITS where id=1";
        // 创建一个数据库连接
        Connection connection = null;
        Statement pstm = null;
        // 创建一个结果集对象
        ResultSet rs = null;
        try {
            //Class.forName("oracle.jdbc.driver.OracleDriver");// 加载Oracle驱动程序
            connection = DriverManager.getConnection(url, user, password);
            pstm = connection.createStatement();
            rs = pstm.executeQuery(sql);
            if (rs != null) {
                while (rs.next()) {
                    wuliao = rs.getString("AMOUNT");
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return wuliao;
    }
}