在JDBC中的QUERY WHERE子句中指定变量名称 [英] Specifying a variable name in QUERY WHERE clause in JDBC

问题描述

有人可以给我一个关于如何在JDBC中创建查询的链接，该查询在WHERE语句中获取变量名，或者编写一个示例，更具体一点，我的代码看起来像这样：

Could someone please give me a link on how to create a query in JDBC that gets a variable name in the WHERE statement, or write an example, to be more specific, my code looks something like this:

      private String getLastModified(String url) {
     String lastModified = null;
     ResultSet resultSet;
String query = "select LastModified from CacheTable where " + 
     " URL.equals(url)";
     try {
      resultSet = sqlStatement.executeQuery(query);
}

现在我需要的语法能让我返回一个ResultSet对象，其中URL在cacheTable等于方法参数的url。

Now I need the syntax that enables me to return a ResultSet object where URL in the cacheTable equals url from the method's argument.

谢谢

推荐答案

最简单的方法是

String query = "select LastModified from CacheTable where url = '" + url +"'";

你应该使用绑定变量：

String query = "select LastModified from CacheTable where url = ?";
prepStmt = conn.prepareStatement(query);
prepStmt.setString(1, url);
rs = prepStmt.executeQuery();

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