json执行sql的工具类

src/main/java/com/sundata/internalevaluation/calc/util/CalciteUtil.java

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+package com.sundata.internalevaluation.calc.util;
+
+import org.apache.calcite.adapter.file.JsonScannableTable;
+import org.apache.calcite.jdbc.CalciteConnection;
+import org.apache.calcite.schema.SchemaPlus;
+import org.apache.calcite.schema.impl.AbstractSchema;
+import org.apache.calcite.util.Sources;
+
+import java.sql.*;
+
+/**
+ * Created by IntelliJ IDEA.
+ *
+ * @author JoeLazy
+ * @date 2025-02-22 15:56:09
+ * @description: json转虚拟数据库、表进行sql查询工具类
+ */
+public class CalciteUtil {
+
+    private Connection connection;
+
+    private SchemaPlus rootSchema;
+
+    private Statement statement;
+
+    private ResultSet resultSet;
+
+    private CalciteUtil() {
+    }
+
+
+    /**
+     * 获取工具类对象实例
+     * @return CalciteUtil
+     * @throws SQLException
+     */
+    public static CalciteUtil getInstance() throws SQLException {
+        CalciteUtil calciteUtil = new CalciteUtil();
+        calciteUtil.createRootSchema();
+        return calciteUtil;
+    }
+
+
+    /**
+     * 创建跟根schema
+     * @throws SQLException
+     */
+    private void createRootSchema() throws SQLException {
+        connection = DriverManager.getConnection("jdbc:calcite:");
+        CalciteConnection calcConnection = connection.unwrap(CalciteConnection.class);
+        rootSchema = calcConnection.getRootSchema();
+    }
+
+
+    /**
+     * 创建 域 （数据库）
+     * @param dbName  数据库名
+     * @return 数据库对应的 Schema
+     */
+    public SchemaPlus createDatabase(String dbName) {
+        return rootSchema.add(dbName, new AbstractSchema());
+    }
+
+
+    /**
+     * 创建表格
+     * @param dbSchema 数据库对应的 Schema
+     * @param tabName 数据表名
+     * @param json listMap对应json    [{a:a1,b:b1},{a:a2,b:b2}...]
+     * @throws SQLException
+     */
+    public void createTable(SchemaPlus dbSchema, String tabName, String json) throws SQLException {
+        if (dbSchema == null) {
+            throw new RuntimeException("dbSchema 不能为空 ！！");
+        }
+        if (rootSchema.getSubSchema(dbSchema.getName()) == null) {
+            throw new RuntimeException("dbSchema不存在！！");
+        } else {
+            dbSchema.add(tabName, new JsonScannableTable(Sources.of(json)));
+        }
+        dbSchema.add(tabName, new JsonScannableTable(Sources.of(json)));
+    }
+
+
+    /**
+     * 执行sql
+     * @param sql sql语句
+     * @return 查询结果（仅返回第一行第一列）    如果无数据返回 null
+     * @throws SQLException
+     */
+    public Object doExecute(String sql) throws SQLException {
+        if (statement == null) {
+            statement = connection.createStatement();
+        }
+        resultSet = statement.executeQuery(sql);
+        if (resultSet.next()) {
+            return resultSet.getObject(1);
+        }
+        return null;
+    }
+
+
+    /**
+     * 关闭资源
+     * @throws SQLException
+     */
+    public void closeResource() throws SQLException {
+        if (resultSet != null) {
+            resultSet.close();
+        }
+        if (statement != null) {
+            statement.close();
+        }
+        if (connection != null) {
+            connection.close();
+        }
+    }
+}