feat: 添加 TableDef 别名缓存。

mybatis-flex-core/src/main/java/com/mybatisflex/core/table/TableDef.java

@@ -18,13 +18,16 @@ package com.mybatisflex.core.table;
 
 import com.mybatisflex.core.query.QueryTable;
 
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Function;
+
 /**
  * 表定义，内包含字段。
  *
  * @author 王帅
  * @since 2024-03-11
  */
-@Deprecated
 public abstract class TableDef extends QueryTable {
 
     protected TableDef(String schema, String tableName) {
@@ -36,13 +39,19 @@ public abstract class TableDef extends QueryTable {
     }
 
     /**
-     * 使用 {@link #getName()} 替代。
+     * 兼容方法，与 {@link #getName()} 相同。
      *
      * @return 表名
      */
-    @Deprecated
     public String getTableName() {
         return name;
     }
 
+    private static final Map<String, TableDef> CACHE = new ConcurrentHashMap<>();
+
+    @SuppressWarnings("unchecked")
+    protected static <V extends TableDef> V getCache(String key, Function<String, V> mappingFunction) {
+        return (V) CACHE.computeIfAbsent(key, mappingFunction);
+    }
+
 }

mybatis-flex-core/src/test/java/com/mybatisflex/coretest/AccountSqlTester.java

@@ -64,6 +64,7 @@ public class AccountSqlTester {
             "  LEFT JOIN ` tb_account ` AS ` a1 ` ON ` a1 `.` id ` = ` ar `.` account_id `\n" +
             "  LEFT JOIN ` tb_account ` AS ` a2 ` ON ` a2 `.` id ` = ` ar `.` account_id `", sql);
         System.out.println(sql);
+        System.out.println(a1 == ACCOUNT.as("a1"));
     }
 
     @Test

mybatis-flex-processor/src/main/java/com/mybatisflex/processor/builder/ContentBuilder.java

@@ -143,7 +143,8 @@ public class ContentBuilder {
             .append("    }\n\n");
 
         content.append("    public ").append(tableDefClassName).append(" as(String alias) {\n")
-            .append("        return new ").append(tableDefClassName).append("(\"").append(schema).append("\", \"").append(tableName).append("\", alias);\n")
+            .append("        String key = getNameWithSchema() + \".\" + alias;\n")
+            .append("        return getCache(key, k -> new ").append(tableDefClassName).append("(\"").append(schema).append("\", \"").append(tableName).append("\", alias));\n")
             .append("    }\n\n}\n");
         return content.toString();
     }