Question

我正在尝试查询一个字符串，该字符串的值对应于sqlite / android studio中的url地址，但它始终引发异常：

E/SQLiteLog: (1) unrecognized token: ":"
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.project, PID: 4525
    android.database.sqlite.SQLiteException: unrecognized token: ":" (code 1): , while compiling: SELECT  * FROM URLS_ITEMS WHERE title = Google AND url = http://www.google.com;
    #################################################################
    Error Code : 1 (SQLITE_ERROR)
    Caused By : SQL(query) error or missing database.
        (unrecognized token: ":" (code 1): , while compiling: SELECT  * FROM URLS_ITEMS WHERE title = Google AND url = http://www.google.com;)
    #################################################################
        at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
        at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:1096)
        at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:661)

下面是引发异常的代码段：

public boolean isUrlAlreadyStored(String title, String url) {
        ArrayList<URLItem> urlDetailList = new ArrayList<URLItem>();
        String query = "SELECT  * FROM " + DATABASE_TABLE_URLS_ITEMS + " WHERE title = " + title + " AND url = " + url + ";";
        Cursor cursor = database.rawQuery(query, null);

我想我应该逃脱字符/令牌：但不确定如何。我尝试过：url = url.replaceAll（“：”，“：”），但显然这不是正确的方法。

有人知道如何查询“ https://www.stackoverflow.com”这样的值/字符串吗？

Answer 1

您可以为SQLite的字符串数据类型添加“'”单引号。

String query = "SELECT  * FROM " + DATABASE_TABLE_URLS_ITEMS + " WHERE title = '" + title + "' AND url = '" + url + "';";

Answer 2

title和url的值是字符串文字，应该用单引号引起来：

String query = "SELECT  * FROM " + DATABASE_TABLE_URLS_ITEMS + " WHERE title = '" + title + "' AND url = '" + url + "';";
Cursor cursor = database.rawQuery(query, null);

但是推荐的安全方法是在语句内使用占位符?，并在title的第二个参数中传递url和rawQuery()的值：

String query = "SELECT  * FROM " + DATABASE_TABLE_URLS_ITEMS + " WHERE title = ? AND url = ?;";
Cursor cursor = database.rawQuery(query, new String[] {title, url});

E / SQLiteLog：（1）无法识别的令牌：“：”

2 个答案: