java - 为什么Android App无法连接Oracle数据库？

Question

我将ojdbc14.jar和oraclepki.jar添加到项目的libs文件夹中，这里是android项目的MainActivity.java:

package com.example.testoracle;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import android.app.Activity;
import android.database.SQLException;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.widget.TextView;
import android.widget.Toast;


public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        try {
            String userName = getDataFromOraDB();
            TextView tv = new TextView(this);
            tv.setText("Here is the name : "+userName);
            setContentView(tv);
            } catch (SQLException e) {
            Toast.makeText(this, "1st toast : "+e.getMessage(), Toast.LENGTH_LONG).show();
            } catch (ClassNotFoundException e) {
            Toast.makeText(this, "second toast : "+e.getMessage(), Toast.LENGTH_LONG).show();
            }
    }

    public String getDataFromOraDB() throws SQLException,
    ClassNotFoundException {
        String name = null;
        String jdbcURL = "jdbc:oracle:thin:@//localhost:1521:oracl";
        String user = "SYSTEM";
        String passwd = "root";
        // Load the Oracle JDBC driver

        try {
            Log.w("MyApp","Try");
            DriverManager.registerDriver(new oracle.jdbc.OracleDriver());
            Connection conn;
            ResultSet rs;
            Statement stmt;
            conn = DriverManager.getConnection(jdbcURL, user, passwd);
            stmt = conn.createStatement();
            Log.w("MyApp","Avant query");
            rs = stmt.executeQuery("select Name from table_people");
            Log.w("MyApp","Apres query");
            if (rs.next()) {
                name = rs.getString("Name");
            }
        } catch (java.sql.SQLException e) {
            // Auto-generated catch block
            System.out.println("the exception is : " + e.toString());
        }

        Toast.makeText(getApplicationContext(), "3rd toast : "+name, Toast.LENGTH_LONG).show();
        return name;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
}

list 确实具有互联网权限

<uses-permission android:name="android.permission.INTERNET" />

这是我在 logcat 中得到的内容

06-01 15:16:34.142: W/MyApp(402): Try
06-01 15:16:34.373: I/dalvikvm(402): Failed resolving Loracle/jdbc/xa/OracleXAResource; interface 927 'Ljavax/transaction/xa/XAResource;'
06-01 15:16:34.373: W/dalvikvm(402): Link of class 'Loracle/jdbc/xa/OracleXAResource;' failed
06-01 15:16:34.373: W/dalvikvm(402): Unable to resolve superclass of Loracle/jdbc/xa/client/OracleXAResource; (1341)
06-01 15:16:34.373: W/dalvikvm(402): Link of class 'Loracle/jdbc/xa/client/OracleXAResource;' failed
06-01 15:16:34.373: W/dalvikvm(402): Unable to resolve superclass of Loracle/jdbc/driver/T4CXAResource; (1348)
06-01 15:16:34.373: W/dalvikvm(402): Link of class 'Loracle/jdbc/driver/T4CXAResource;' failed
06-01 15:16:34.373: W/dalvikvm(402): VFY: unable to find class referenced in signature (Loracle/jdbc/driver/T4CXAResource;)
06-01 15:16:34.373: I/dalvikvm(402): Failed resolving Loracle/jdbc/xa/OracleXAResource; interface 927 'Ljavax/transaction/xa/XAResource;'
06-01 15:16:34.383: W/dalvikvm(402): Link of class 'Loracle/jdbc/xa/OracleXAResource;' failed
06-01 15:16:34.383: W/dalvikvm(402): Unable to resolve superclass of Loracle/jdbc/xa/client/OracleXAResource; (1341)
06-01 15:16:34.383: W/dalvikvm(402): Link of class 'Loracle/jdbc/xa/client/OracleXAResource;' failed
06-01 15:16:34.383: W/dalvikvm(402): Unable to resolve superclass of Loracle/jdbc/driver/T4CXAResource; (1348)
06-01 15:16:34.383: W/dalvikvm(402): Link of class 'Loracle/jdbc/driver/T4CXAResource;' failed
06-01 15:16:34.383: I/dalvikvm(402): Could not find method oracle.jdbc.driver.T4CXAResource.setPasswordInternal, referenced from method oracle.jdbc.driver.T4CConnection.getPasswordInternal
06-01 15:16:34.383: W/dalvikvm(402): VFY: unable to resolve virtual method 10574: Loracle/jdbc/driver/T4CXAResource;.setPasswordInternal (Ljava/lang/String;)V
06-01 15:16:34.533: I/dalvikvm(402): Failed resolving Loracle/jdbc/pool/OracleDataSource; interface 850 'Ljavax/naming/Referenceable;'
06-01 15:16:34.533: W/dalvikvm(402): Link of class 'Loracle/jdbc/pool/OracleDataSource;' failed
06-01 15:16:34.533: I/dalvikvm(402): Could not find method oracle.jdbc.pool.OracleDataSource.filterConnectionProperties, referenced from method oracle.jdbc.driver.PhysicalConnection.getProperties
06-01 15:16:34.533: W/dalvikvm(402): VFY: unable to resolve static method 11805: Loracle/jdbc/pool/OracleDataSource;.filterConnectionProperties (Ljava/util/Properties;)Ljava/util/Properties;
06-01 15:16:34.543: W/dalvikvm(402): VFY: unable to find class referenced in signature (Ljavax/transaction/xa/XAResource;)
06-01 15:16:35.192: I/System.out(402): the exception is : java.sql.SQLException: Io exception: The Network Adapter could not establish the connection

那么有没有办法避免“网络适配器无法建立连接”？

Answer 1

这可能不是您想听到的，但是......

虽然您可能可以通过使用正确的数据库服务器地址并摆弄一堆其他位来实现此目的，但您确实不应该这样做。

Oracle 是一种服务器端技术，而 Android 显然是一种客户端技术。大多数理智的人在很多年前就停止使用这种客户端-服务器数据库访问，原因非常充分......以至于现在它几乎成了一个怀旧的笑话。

恕我直言，您应该使用您选择的语言构建一个服务器应用程序，为您的 Android 应用程序提供基于 HTTP 的 API(XML、JSON 等)。

然后，直接从 Android 应用程序使用 API，或者使用 API 使 Android 的本地 sqlite 数据库与 Oracle 数据库的某些子集保持同步。

有很多通过您最喜欢的网络搜索引擎实现这两种操作的示例。