com.xiaoleilu.hutool.db.handler.HandleHelper Maven / Gradle / Ivy

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package com.xiaoleilu.hutool.db.handler;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Types;
import java.util.Collection;

import com.xiaoleilu.hutool.db.Entity;

/**
 * 数据结果集处理辅助类
 * @author loolly
 *
 */
public class HandleHelper {
	
	/**
	 * 处理单条数据
	 * @param columnCount 列数
	 * @param meta ResultSetMetaData
	 * @param rs 数据集
	 * @return 每一行的Entity
	 * @throws SQLException SQL执行异常
	 */
	public static Entity handleRow(int columnCount, ResultSetMetaData meta, ResultSet rs) throws SQLException {
		return handleRow(Entity.create(), columnCount, meta, rs);
	}
	
	/**
	 * 处理单条数据
	 * 
	 * @param  Entity及其子对象
	 * @param row Entity对象
	 * @param columnCount 列数
	 * @param meta ResultSetMetaData
	 * @param rs 数据集
	 * @return 每一行的Entity
	 * @throws SQLException SQL执行异常
	 * @since 3.3.0
	 */
	public static  T handleRow(T row, int columnCount, ResultSetMetaData meta, ResultSet rs) throws SQLException {
		row.setTableName(meta.getTableName(1));
		String columnLabel;
		int type;
		for (int i = 1; i <= columnCount; i++) {
			columnLabel = meta.getColumnLabel(i);
			type = meta.getColumnType(i);
			row.put(columnLabel, getColumnValue(rs, columnLabel, type));
		}
		return row;
	}
	
	/**
	 * 处理单条数据
	 * @param rs 数据集
	 * @return 每一行的Entity
	 * @throws SQLException SQL执行异常
	 */
	public static Entity handleRow(ResultSet rs) throws SQLException {
		final ResultSetMetaData meta = rs.getMetaData();
		final int columnCount = meta.getColumnCount();
		return handleRow(columnCount, meta, rs);
	}
	
	/**
	 * 处理多条数据
	 * @param  集合类型
	 * @param rs 数据集
	 * @param collection 数据集
	 * @return Entity列表
	 * @throws SQLException SQL执行异常
	 */
	public static > T handleRs(ResultSet rs, T collection) throws SQLException {
		final ResultSetMetaData  meta = rs.getMetaData();
		final int columnCount = meta.getColumnCount();
		
		while(rs.next()) {
			collection.add(HandleHelper.handleRow(columnCount, meta, rs));
		}
		
		return collection;
	}
	
	/**
	 * 处理多条数据并返回一个Bean列表
	 * 
	 * @param  集合元素类型
	 * @param  集合类型
	 * @param rs 数据集
	 * @param collection 数据集
	 * @param elementBeanType Bean类型
	 * @return Entity列表
	 * @throws SQLException SQL执行异常
	 * @since 3.1.0
	 */
	public static > T handleRsToBeanList(ResultSet rs, T collection, Class elementBeanType) throws SQLException {
		final ResultSetMetaData  meta = rs.getMetaData();
		final int columnCount = meta.getColumnCount();
		
		while(rs.next()) {
			collection.add(HandleHelper.handleRow(columnCount, meta, rs).toBean(elementBeanType));
		}
		
		return collection;
	}
	
	//-------------------------------------------------------------------------------------------------------------- Private method start
	/**
	 * 获取字段值

	 * 针对日期时间等做单独处理判断
	 * 
	 * @param rs {@link ResultSet}
	 * @param label 字段名
	 * @param type 字段类型，默认Object
	 * @return 字段值
	 * @throws SQLException SQL异常
	 * @since 3.2.3
	 */
	private static Object getColumnValue(ResultSet rs, String label, int type) throws SQLException {
		switch (type) {
		case Types.TIMESTAMP:
			return rs.getTimestamp(label);
		case Types.TIME:
			return rs.getTime(label);
		default:
			return rs.getObject(label);
		}
	}
	//-------------------------------------------------------------------------------------------------------------- Private method end
}