基於Spring的JdbcTemplate和Hibernate產生的BaseDao（一）

最近在看各類持久層 發現每個框架提供的關於JDBC的封裝都有限 我就按照易於擴展、靈活、簡單方便的思路寫了一個關於數據庫持久層的操做 BaseDao

思路是這樣的：

    BaseDao要有以下的功能

     1 對於簡單的增刪改查採用hibernate提供的HibernateDaoSupport

     2 對於複雜的連接查詢或者統計能夠本身寫sql語句

因而就寫了以下的一個BaseDao  帶分頁功能的。

package com.sod.dao.base;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.orm.hibernate3.HibernateTemplate;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import com.sod.dao.dialect.MysqlDialect;
import com.sod.entity.sys.SodUser;


public class BaseDao<T> extends HibernateDaoSupport {
	private JdbcTemplate jdbcTemplate;

	public JdbcTemplate getJdbcTemplate() {
		return jdbcTemplate;
	}
	@Autowired
	public void setJT(JdbcTemplate jdbcTemplate) {
		this.jdbcTemplate = jdbcTemplate;
	}
	@Autowired
	public void setHT(HibernateTemplate hibernateTemplate) {
		super.setHibernateTemplate(hibernateTemplate);
	}
	public Page<T> paginate(String sql,int pageNumber, int pageSize,Class<T> clazz,Object... paras) {
		if (pageNumber < 1) {
			pageNumber = 1;
		}
		if (pageSize < 1) {
			pageSize = Page.DEFAULT_PAGE_SIZE;
		}
		long totalRow = 0;
		int totalPage = 0;
		//獲取記錄總數
		totalRow = getJdbcTemplate().queryForLong(getSQLCount(sql));
		if (totalRow == 0) {
			return new Page<T>(new ArrayList<T>(0), pageNumber, pageSize, 0, 0);	// totalRow = 0;
		}
		totalPage = (int) (totalRow / pageSize);
		if (totalRow % pageSize != 0) {
			totalPage++;
		}
		//獲取mysql的分頁sql
		String paginateSql = MysqlDialect.getInstance().bulidPaginateSql(sql, pageNumber, pageSize);
		List<Map<String, Object>> list = getJdbcTemplate().queryForList(paginateSql.toString());
		List<T> tList = getList(list,clazz);
		return new Page<T>(tList, pageNumber, pageSize, totalPage, totalRow);
		
	}
	
	public String getSQLCount(String sql){  
        String sqlBak = sql.toLowerCase();  
        String searchValue = " from ";  
        String sqlCount = "select count(*) from "+ sql.substring(sqlBak.indexOf(searchValue)+searchValue.length(), sqlBak.length());  
        return sqlCount;  
    }  
	
	public List<T> getList(List<Map<String, Object>> list,
			Class<T> clazz){
		List<T> listRes = new ArrayList<T>();
		for (Map<String, Object> item : list) {
			T obj;
			try {
				obj = clazz.newInstance();
				Iterator<Entry<String, Object>> iter = item.entrySet()
						.iterator();
				while (iter.hasNext()) {
					Map.Entry<String, Object> entry = (Map.Entry<String, Object>) iter
							.next();

					Object objKey = entry.getKey();
					Object val = entry.getValue();
					String key = treat(objKey.toString());
					Field fieldItem = getDeclaredField(clazz,key);
					if (fieldItem != null) {
						fieldItem.setAccessible(true);
						fieldItem.set(obj, val);
					}
				}
				listRes.add(obj);
				// log(item.toString()+":");
				for (Object it : item.values()) {
					if (it != null) {
						it.toString();
						// log(it.toString());
					}
				}
			} catch (InstantiationException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (IllegalAccessException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (SecurityException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return listRes;
	}

	public Field getDeclaredField(Class<?> clazz, String fieldName) {
		Field field = null;
		for (; clazz != Object.class; clazz = clazz.getSuperclass()) {
			try {
				field = clazz.getDeclaredField(fieldName);
				return field;
			} catch (Exception e) {
				
			}
		}
		return field;

	}
	private String treat(String objKey) {
		String str = objKey;
		if (objKey.indexOf("_") != -1) {
			String[] strArr = objKey.split("_");
			String strRes = strArr[0];
			for (int i = 1; i < strArr.length; i++) {
				strRes = strRes + strArr[i].substring(0, 1).toUpperCase()
						+ strArr[i].substring(1);
			}
			str = strRes;
		}

		return str;
	}
	
	public static void main(String[] args) throws IllegalArgumentException, IllegalAccessException {
		BaseDao<SodUser> bd = new BaseDao<SodUser>();
		Field f = bd.getDeclaredField(SodUser.class, "id1");
		SodUser user = new SodUser();
		f.setAccessible(true);
		f.set(user, new Integer(100));
		System.out.println(user.getId());
	}
}

分頁Page類

package com.sod.dao.base;

import java.io.Serializable;
import java.util.List;

/** 
 * @author  zhaobb   
 * @version 建立時間：2012-12-16 上午10:13:20 
 * 類說明 ：
 */
public class Page<T>  implements Serializable{
	private static final long serialVersionUID = 1L;
	
	public static final int DEFAULT_PAGE_SIZE = 3;
	
	private List<T> list;				// list result of this page
	private int pageNumber;				// page number
	private int pageSize;				// result amount of this page
	private int totalPage;				// total page
	private long totalRow;				// total row
	
	
	public Page(List<T> list, int pageNumber, int pageSize, int totalPage, long totalRow) {
		this.list = list;
		this.pageNumber = pageNumber;
		this.pageSize = pageSize;
		this.totalPage = totalPage;
		this.totalRow = totalRow;
	}
	
	/**
	 * Return list of this page.
	 */
	public List<T> getList() {
		return list;
	}
	
	/**
	 * Return page number.
	 */
	public int getPageNumber() {
		return pageNumber;
	}
	
	/**
	 * Return page size.
	 */
	public int getPageSize() {
		return pageSize;
	}
	
	/**
	 * Return total page.
	 */
	public int getTotalPage() {
		return totalPage;
	}
	
	/**
	 * Return total row.
	 */
	public long getTotalRow() {
		return totalRow;
	}
}

寫了一個Mysql 方言分頁處理類MysqlDialect 這個是看了JFinal源碼想到的

/**
 * Copyright (c) 2011-2012, James Zhan 詹波 (jfinal@126.com).
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.sod.dao.dialect;


/**
 * MysqlDialect.
 */
public class MysqlDialect {
	
	static MysqlDialect mydialect = new MysqlDialect();
	
	private MysqlDialect(){
		
	}
	public static MysqlDialect getInstance(){
		if (mydialect == null) {
			mydialect = new MysqlDialect();
		}
		return mydialect;
	}
	public String forTableInfoBuilderDoBuildTableInfo(String tableName) {
		return "select * from `" + tableName + "` where 1 = 2";
	}
	
	
	public String forDbFindById(String tableName, String primaryKey, String columns) {
		StringBuilder sql = new StringBuilder("select ");
		if (columns.trim().equals("*")) {
			sql.append(columns);
		}
		else {
			String[] columnsArray = columns.split(",");
			for (int i=0; i<columnsArray.length; i++) {
				if (i > 0)
					sql.append(", ");
				sql.append("`").append(columnsArray[i].trim()).append("`");
			}
		}
		sql.append(" from `");
		sql.append(tableName.trim());
		sql.append("` where `").append(primaryKey).append("` = ?");
		return sql.toString();
	}
	
	public String forDbDeleteById(String tableName, String primaryKey) {
		StringBuilder sql = new StringBuilder("delete from `");
		sql.append(tableName.trim());
		sql.append("` where `").append(primaryKey).append("` = ?");
		return sql.toString();
	}
	
	public String bulidPaginateSql(String sql ,int pageNumber, int pageSize) {
		StringBuilder paginationSQL = new StringBuilder();
		int offset = pageSize * (pageNumber - 1);
		paginationSQL.append(sql);
		paginationSQL.append(" limit ").append(offset).append(", ").append(pageSize);	// limit can use one or two '?' to pass paras
		return paginationSQL.toString();
	
	}
	
	public boolean isSupportAutoIncrementKey() {
		return true;
	}
}

下面是BaseDao的一個應用SodUserDao類

package com.sod.dao.sys;

import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.simple.ParameterizedBeanPropertyRowMapper;
import org.springframework.stereotype.Repository;

import com.sod.dao.base.BaseDao;
import com.sod.dao.base.Page;
import com.sod.entity.sys.SodUser;

/** 
 * @author  zhaobb   
 * @version 建立時間：2012-12-15 上午10:56:49 
 * 類說明 ：
 */
@Repository
public class SodUserDao extends BaseDao<SodUser>{
	
	
	public Integer save(SodUser user){
		Integer id = (Integer)getHibernateTemplate().save(user);
		return id;
	}
	
	public SodUser getById(int id){
		return getHibernateTemplate().get(SodUser.class, id);
	}
	
	public Page<SodUser> findUserByPage(int pageSize, int pageNumber){
		String sql = "select * from sod_user";
		Page<SodUser> page = paginate(sql, pageNumber, pageSize,SodUser.class);
		return page;
	}
}

上面的 SodUserDao中分頁功能是本身寫的一個sql語句 ，沒有采用hibernate的分頁功能。

基本就這些了，但願專家指正。哈哈