@ConditionalOnProperty(value = "elasticsearch.enabled", havingValue = "true")

这是一个Spring Boot的注解`@ConditionalOnProperty`，它用于在满足指定条件时才加载Bean。在这个例子中，它的条件是`elasticsearch.enabled`属性值为`true`。如果该属性值为`true`，则相关的Bean会被加载；如果该属性值不为`true`或未配置，相关的Bean将不会被加载。这个注解通常用于根据配置文件中的属性来动态决定是否加载某些Bean。

相关问题

Elasticsearch SQL Access

Sure, I can help you with Elasticsearch SQL access. Elasticsearch provides a SQL API that allows you to query data using SQL syntax. To access Elasticsearch using SQL, you need to follow these steps:

1. Install the necessary software: You need to install Elasticsearch and the appropriate version of the Elasticsearch JDBC driver for your programming language or client.

2. Configure Elasticsearch: Enable the SQL feature in your Elasticsearch configuration file. You can do this by setting `xpack.sql.enabled: true` in the `elasticsearch.yml` file.

3. Connect to Elasticsearch: Establish a connection to your Elasticsearch cluster using the JDBC driver. The connection string will depend on your specific setup and programming language.

4. Execute SQL queries: Once connected, you can execute SQL queries against Elasticsearch. The queries can include standard SQL statements like SELECT, INSERT, UPDATE, and DELETE, as well as Elasticsearch-specific extensions for full-text search and complex aggregations.

Here's an example of how to query Elasticsearch using SQL in Java:

import java.sql.*;

public class ElasticsearchSQLAccess {
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        
        try {
            // Register the JDBC driver
            Class.forName("org.elasticsearch.xpack.sql.jdbc.EsDriver");
            
            // Open a connection
            conn = DriverManager.getConnection("jdbc:es://localhost:9200");
            
            // Create a statement
            stmt = conn.createStatement();
            
            // Execute a query
            String sql = "SELECT * FROM index_name WHERE field_name = 'value'";
            rs = stmt.executeQuery(sql);
            
            // Process the result set
            while (rs.next()) {
                // Access the retrieved data
                String field1 = rs.getString("field1");
                int field2 = rs.getInt("field2");
                
                // Do something with the data
                
            }
        } catch (SQLException | ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            // Close the connections
            try { rs.close(); } catch (Exception ignored) {}
            try { stmt.close(); } catch (Exception ignored) {}
            try { conn.close(); } catch (Exception ignored) {}
        }
    }
}

Remember to replace `index_name`, `field_name`, and the connection details with your actual values.

That's a basic overview of how to access Elasticsearch using SQL. You can refer to the Elasticsearch documentation for more information on supported SQL syntax and examples for other programming languages.

elasticsearch-8.15用户名密码

Elasticsearch 8.15 的用户名和密码是用来管理集群安全性的。当你设置一个新集群或者对现有集群进行配置时，你需要创建一个管理员用户（有时也称为超级用户），用于登录并进行权限管理操作。

通常，你可以通过`elasticsearch.yml`文件或命令行工具如`curl`来配置基本的HTTP身份验证。例如，在`elasticsearch.yml`中添加如下内容：

http.cors.enabled: true
http.cors.allow-origin: "*"
http.cors.support.credentials: true
xpack.security.transport.mode: basic
xpack.security.authcz.policies: default
xpack.security.user.MM_admin_user: "MM_admin_password"

这里，`MM_admin_user`是你自定义的用户名，`MM_admin_password`则是对应的明文密码，注意实际生产环境中建议使用环境变量或加密存储。

为了设置用户，可以使用`PUT _xpack/security/user/MM_admin_user`的API，并提供适当的JSON配置，包括角色、权限等。然后通过`GET /_cluster/settings`确认配置是否生效。

如果你是在命令行操作，可以使用类似下面的`curl`命令（需要先启动X-Pack插件）：

curl -X PUT 'localhost:9200/_xpack/security/user/MM_admin_user?password=your_password' -H 'Content-Type: application/json' -d'
{
  "password": {
    "enabled": true,
    "value": "your_password"
  },
  "roles": ["superuser"]
}'