Question

这里的简单问题我遇到了问题，只有我发现的教程在我的IDE（Eclipse with Maven）中产生了很多错误。我现在可以阅读我的JSON响应，但我想将它们写入（并最终将它们转换）给我的Cassandra DB。任何人都有一些他们可以分享的基本代码让我开始这个？

Answer 1

datastax java-driver包含几个用于使用Jackson，Jsr353或纯文本从cassandra写入/读取JSON的示例，它可以在驱动程序示例here中找到。

以下是来自PlainTextJson.java的示例，显示如何作为字符串插入：

private static void insertWithCoreApi(Session session) {
    // Bind in a simple statement:
    session.execute("INSERT INTO examples.querybuilder_json JSON ?",
            "{ \"id\": 1, \"name\": \"Mouse\", 
               \"specs\": { \"color\": \"silver\" } }");

    // Bind in a prepared statement:
    // (we use a local variable here for the sake of example, but in a real application you would cache and reuse
    // the prepared statement)
    PreparedStatement pst = session.prepare(
        "INSERT INTO examples.querybuilder_json JSON :payload");
    session.execute(pst.bind()
            .setString("payload", 
                "{ \"id\": 2, \"name\": \"Keyboard\",
                   \"specs\": { \"layout\": \"qwerty\" } }"));

    // fromJson lets you provide individual columns as JSON:
    session.execute("INSERT INTO examples.querybuilder_json " +
                    "(id, name, specs)  VALUES (?, ?, fromJson(?))",
            3, "Screen", "{ \"size\": \"24-inch\" }");
}

用于将JSON响应写入Cassandra的示例Java代码？

1 个答案: