refactor: 提取 ResultHandler.mapToList 消除 ResultSet 遍历重复代码

src/main/java/xyz/zhouxy/jdbc/JdbcOperationSupport.java

@@ -37,8 +37,6 @@ import java.util.List;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
-import com.google.common.collect.Lists;
-
 /**
  * JdbcOperationSupport
  *
@@ -184,18 +182,13 @@ class JdbcOperationSupport {
         assertConnectionNotNull(conn);
         assertSqlNotNull(sql);
         assertRowMapperNotNull(rowMapper);
-        final List<T> result = Lists.newArrayListWithCapacity(4);
         try (PreparedStatement stmt = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) {
             fillStatement(stmt, params);
             stmt.executeUpdate();
             try (ResultSet generatedKeys = stmt.getGeneratedKeys()) {
-                int rowNumber = 0;
-                while (generatedKeys.next()) {
-                    T e = rowMapper.mapRow(generatedKeys, rowNumber++);
-                    result.add(e);
-                }
+                final ResultHandler<List<T>> resultHandler = ResultHandler.mapToList(rowMapper);
+                return resultHandler.handle(generatedKeys);
             }
-            return result;
         }
     }
 
@@ -324,15 +317,7 @@ class JdbcOperationSupport {
                                                  @Nullable Object[] params,
                                                  @Nonnull RowMapper<T> rowMapper)
             throws SQLException {
-        return queryInternal(conn, sql, params, rs -> {
-            List<T> result = Lists.newArrayList();
-            int rowNumber = 0;
-            while (rs.next()) {
-                T e = rowMapper.mapRow(rs, rowNumber++);
-                result.add(e);
-            }
-            return result;
-        });
+        return queryInternal(conn, sql, params, ResultHandler.mapToList(rowMapper));
     }
 
     /**

src/main/java/xyz/zhouxy/jdbc/ResultHandler.java

@@ -18,6 +18,8 @@ package xyz.zhouxy.jdbc;
 
 import java.sql.ResultSet;
 import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.List;
 
 /**
  * ResultHandler
@@ -41,4 +43,26 @@ public interface ResultHandler<T> {
      * @throws SQLException 数据库执行异常
      */
     T handle(ResultSet resultSet) throws SQLException;
+
+    /**
+     * 创建一个返回 {@link List} 的 {@link ResultHandler}，将 {@link ResultSet} 中的每一行
+     * 通过指定的 {@link RowMapper} 映射为对象，最终收集为一个 {@link List}。
+     *
+     * @param <T>        列表元素类型
+     * @param rowMapper  行映射器，用于将 {@link ResultSet} 的单行转换为对象
+     * @return 返回 {@code List<T>} 的 {@code ResultHandler}
+     * @since 1.0.0
+     * @see RowMapper
+     */
+    static <T> ResultHandler<List<T>> mapToList(RowMapper<T> rowMapper) {
+        return resultSet -> {
+            List<T> result = new ArrayList<>();
+            int rowNumber = 0;
+            while (resultSet.next()) {
+                T e = rowMapper.mapRow(resultSet, rowNumber++);
+                result.add(e);
+            }
+            return result;
+        };
+    }
 }