尝试复制数据库时发生IO异常故障

Question

我想创建一个SqliteManager类来使用Sqlite数据库。但当我试图复制数据库时，我得到了一个IO错误。这是我的代码：

            try {
                copyDataBase();
            } catch (IOException e) {
                throw new Error(e.getMessage());
            }

我正试图在这里复制数据库。

     private void copyDataBase() throws IOException {
        InputStream myInput = helperContext.getAssets().open(DATABASE_NAME);
        String outFileName = DB_PATH + DATABASE_NAME;
        OutputStream myOutput = new FileOutputStream(outFileName);
        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer)) > 0) {
            myOutput.write(buffer, 0, length);
        }
        myOutput.flush();
        myOutput.close();
        myInput.close();
    }

这是我的copyDatabase函数。我在这里得到错误myOutput.write(buffer, 0, length);。

11-23 10:38:23.005: ERROR/AndroidRuntime(531): Uncaught handler: thread main exiting due to uncaught exception
11-23 10:38:23.585: ERROR/AndroidRuntime(531): java.lang.Error
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at cf.android.dbsmpl.SqliteManager$DatabaseHelper.createDataBase(SqliteManager.java:291)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at cf.android.dbsmpl.SqliteManager.open(SqliteManager.java:60)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at cf.android.dbsmpl.MainMenu.onCreate(MainMenu.java:31)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.app.ActivityThread.startActivityNow(ActivityThread.java:2335)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:648)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.widget.TabHost.setCurrentTab(TabHost.java:320)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.widget.TabHost.addTab(TabHost.java:213)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at cf.android.dbsmpl.DbsmplMainActivity.onCreate(DbsmplMainActivity.java:27)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.app.ActivityThread.access$2200(ActivityThread.java:119)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.os.Handler.dispatchMessage(Handler.java:99)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.os.Looper.loop(Looper.java:123)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at android.app.ActivityThread.main(ActivityThread.java:4363)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at java.lang.reflect.Method.invokeNative(Native Method)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at java.lang.reflect.Method.invoke(Method.java:521)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
11-23 10:38:23.585: ERROR/AndroidRuntime(531):     at dalvik.system.NativeStart.main(Native Method)

这是错误日志。当我调试这个代码时，它显示这个错误的原因是IOException。我被卡住了，我希望你能帮我弄清楚问题出在哪里。感谢

Answer 1

private void copyDataBase() throws IOException {
    InputStream myInput = new FileInputStream("/data/data/com.dinota.emc/databases/UFS-SG.db"); //change this to your original location
    String outFileName = "/data/data/com.dinota.emc/databases/" + "UFS-SG.db1"; //change this location as well
    OutputStream myOutput = new FileOutputStream(outFileName);
    byte[] buffer = new byte[myInput.available()];
    int length;
    while ((length = myInput.read(buffer)) > 0) {
        myOutput.write(buffer, 0, length);
    }
    myOutput.flush();
    myOutput.close();
    myInput.close();
}

试试这个方法。这没有任何问题。。