hibernate通用 BaseDao(通用分頁)
阿新 • • 發佈:2018-12-19
基於分頁的通用類 StringUtils 類
package com.eight.dao; public class StringUtils { // 私有的構造方法,保護此類不能在外部例項化 private StringUtils() { } /** * 如果字串等於null或去空格後等於"",則返回true,否則返回false * * @param s * @return */ public static boolean isBlank(String s) { boolean b = false; if (null == s || s.trim().equals("")) { b = true; } return b; } /** * 如果字串不等於null或去空格後不等於"",則返回true,否則返回false * * @param s * @return */ public static boolean isNotBlank(String s) { return !isBlank(s); } }
pageBean 分頁工具類
/** * 分頁工具類 * */ public class PageBean { private int page = 1;// 頁碼 private int rows = 3;// 頁大小 private int total = 0;// 總記錄數 private boolean pagination = true;// 是否分頁 // 獲取前臺向後臺提交的所有引數 private Map<String, String[]> parameterMap; // 獲取上一次訪問後臺的url private String url; /** * 初始化pagebean * * @param req */ public void setRequest(HttpServletRequest req) { this.setPage(req.getParameter("page")); this.setRows(req.getParameter("rows")); // 只有jsp頁面上填寫pagination=false才是不分頁 this.setPagination(!"fasle".equals(req.getParameter("pagination"))); this.setParameterMap(req.getParameterMap()); this.setUrl(req.getRequestURL().toString()); } public int getMaxPage() { return this.total % this.rows == 0 ? this.total / this.rows : this.total / this.rows + 1; } public int nextPage() { return this.page < this.getMaxPage() ? this.page + 1 : this.getMaxPage(); } public int previousPage() { return this.page > 1 ? this.page - 1 : 1; } public PageBean() { super(); } public int getPage() { return page; } public void setPage(int page) { this.page = page; } public void setPage(String page) { this.page = StringUtils.isBlank(page) ? this.page : Integer.valueOf(page); } public int getRows() { return rows; } public void setRows(int rows) { this.rows = rows; } public void setRows(String rows) { this.rows = StringUtils.isBlank(rows) ? this.rows : Integer.valueOf(rows); } public int getTotal() { return total; } public void setTotal(int total) { this.total = total; } public void setTotal(String total) { this.total = Integer.parseInt(total); } public boolean isPagination() { return pagination; } public void setPagination(boolean pagination) { this.pagination = pagination; } public Map<String, String[]> getParameterMap() { return parameterMap; } public void setParameterMap(Map<String, String[]> parameterMap) { this.parameterMap = parameterMap; } public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } /** * 獲得起始記錄的下標 * * @return */ public int getStartIndex() { return (this.page - 1) * this.rows; } @Override public String toString() { return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination + ", parameterMap=" + parameterMap + ", url=" + url + "]"; } }
BaseDao
package com.eight.dao; import java.util.Collection; import java.util.List; import java.util.Map; import org.hibernate.Session; import org.hibernate.query.Query; import org.omg.CORBA.OBJ_ADAPTER; /** * 作用: 1,將賦值的操作交給basedao處理 2,分頁 a,查詢出條件的總記錄數 b,查詢符合條件的某一頁記錄 * * @author YGUUU * */ public class BaseDao { /** * 賦值的操作 * * @param query * 預定義物件 * @param map * 前臺傳遞過來的引數 */ public void setParameter(Query query, Map<String, Object> map) { // query.setParameter("bookName", "%"+book.getBookName()+"%"); if (map == null || map.size() == 0) { return; } Object value = null; for (Map.Entry<String, Object> entry : map.entrySet()) { value = entry.getValue(); if (value instanceof Collection) { query.setParameterList(entry.getKey(), (Collection) value); } else if (value instanceof Object[]) { query.setParameterList(entry.getKey(), (Object[]) value); } else { query.setParameter(entry.getKey(), value); } } } public void ser(Query query, Map<String, Object> map) { if (map == null && map.size() == 0) { return; } Object value = null; for (Map.Entry<String, Object> entry : map.entrySet()) { value = entry.getValue(); if (value instanceof Collection) { query.setParameterList(entry.getKey(), (Collection) value); } else if (value instanceof Object[]) { query.setParameterList(entry.getKey(), (Object[]) value); } else { query.setParameter(entry.getKey(), value); } } } /** * select * from t_hibernate_book where book_name like '%聖墟%' countSql = select * count(*) from (select * from t_hibernate_book where book_name like '%聖墟%') t * pageSql = sql+" limit ?,?" hibernate中這一步省略 * * hql = from Book where 1=1 and bookName like '%聖墟%' hql = select * bookName,price from Book where 1=1 and bookName like '%聖墟%' * * 思路: 擷取from後面的sql語句,前面拼接select count(*) from轉成大寫 */ /** * 查詢出條件的總記錄數 * * @param hql * @return */ public String getCountHql(String hql) { int indexOf = hql.toUpperCase().indexOf("FROM"); return "select count(*) " + hql.substring(indexOf); } public List executeQuery(Session session, String hql, PageBean pageBean, Map<String, Object> map) { if (pageBean != null && pageBean.isPagination()) { // select count(*) from t_hibernate_book where book_name like '%聖墟%' String countHql = getCountHql(hql); Query Countquery = session.createQuery(countHql); this.setParameter(Countquery, map); // pageBean設定總記錄數,用於分頁 pageBean.setTotal(Countquery.getSingleResult().toString()); // 查詢展示的資料 Query pageQuery = session.createQuery(hql); this.setParameter(pageQuery, map); pageQuery.setFirstResult(pageBean.getStartIndex()); pageQuery.setMaxResults(pageBean.getRows()); return pageQuery.list(); } else { Query query = session.createQuery(hql); this.setParameter(query, map); return query.list(); } } }
繼承basedao
package com.five.dao;
import java.io.Serializable;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.hibernate.Hibernate;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.query.Query;
import com.zking.eight.dao.BaseDao;
import com.zking.eight.dao.PageBean;
import com.zking.eight.dao.StringUtils;
import com.zking.five.entity.Book;
import com.zking.two.util.SessionFactoryUtils;
public class BookDao extends BaseDao{
public List<Book> list1(Book book,PageBean pageBean){
Session session = SessionFactoryUtils.getSession();
Transaction transaction = session.beginTransaction();
String hql="from Book where 1=1";
if(StringUtils.isNotBlank(book.getBookName())) {
hql+=" and bookName like :bookName";
}
Query query = session.createQuery(hql);
if(StringUtils.isNotBlank(book.getBookName())) {
query.setParameter("bookName", "%"+book.getBookName()+"%");
}
if(pageBean!=null&&pageBean.isPagination()) {
query.setFirstResult(pageBean.getStartIndex());
query.setMaxResults(pageBean.getRows());
}
List list = query.list();
transaction.commit();
session.close();
return list;
}
public List<Book> list2(Book book,PageBean pageBean){
Session session = SessionFactoryUtils.getSession();
Transaction transaction = session.beginTransaction();
Map<String, Object> map=new HashMap<>();
String hql="from Book where 1=1";
if(StringUtils.isNotBlank(book.getBookName())) {
hql+=" and bookName like :bookName";
map.put("bookName", book.getBookName());
}
//沒寫BaseDao前,你上面寫了多少個判斷,下面就要寫多少個判斷加分頁的一個判斷,寫 了BaseDao後,直接呼叫這個executeQuery 就行了
List list = super.executeQuery(session, hql, pageBean, map);
transaction.commit();
session.close();
return list;
}
public List<Object[]> list3(){
Session session = SessionFactoryUtils.getSession();
Transaction transaction = session.beginTransaction();
Map<String, Object> map=new HashMap<>();
// String hql="select b.bookName,o.orderNo from Book b,Order o where 1=1";
// String sql="select b.book_name,o.order_no from t_hibernate_book b,t_hibernate_order o where 1=1";
String sql="select * from book_order";
// List list = session.createQuery(hql).list();
List list = session.createSQLQuery(sql).list();
transaction.commit();
session.close();
return list;
}
}
測試方法
private BookDao bookDao=new BookDao();
@Test
public void testList1() {
PageBean pageBean=new PageBean();
// pageBean.setPage(2);
Book book=new Book();
book.setBookName("斗羅大陸");
List<Book> list1 = this.bookDao.list1(book, pageBean);
for (Book b : list1) {
System.out.println(b);
}
}
@Test
public void testList2() {
PageBean pageBean=new PageBean();
// pageBean.setPage(2);
Book book=new Book();
book.setBookName("斗羅大陸");
List<Book> list1 = this.bookDao.list2(book, pageBean);
for (Book b : list1) {
System.out.println(b);
}
}
@Test
public void testList3() {
PageBean pageBean=new PageBean();
pageBean.setPage(2);
Book book=new Book();
// book.setBookName("斗羅大陸");
List<Object[]> list1 = this.bookDao.list3();
for (Object[] b : list1) {
System.out.println(Arrays.toString(b));
}
}
原生sql hql實現不了的功能,可以考慮使用原生sql 1、多表(5+)聯查 2、未配置對映檔案中關係
public List<Object[]> list3(){
Session session = SessionFactoryUtils.getSession();
Transaction transaction = session.beginTransaction();
Map<String, Object> map=new HashMap<String, Object>();
// String hql="select b.bookName,o.OrderNo from Book b,Order o where 1=1";
// String sql="select b.book_name,o.order_no from t_hibernate_book b,t_hibernate_Order o where 1=1";//原生態sql
String sql="select * from book_order";//檢視對映
// List list = session.createQuery(hql).list();
List list = session.createSQLQuery(sql).list();
transaction.commit();
session.close();
return list;
}
檢視對映 場景 select * from 3表聯查 建立檢視 建立檢視實體類(注:實體類要實現 Serializable介面)
package com.zking.eight.entity;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;
import com.zking.five.entity.Category;
public class BookOrder implements Serializable{
private Integer book_id;
private Integer order_id;
private String bookName;
private String OrderNo;
public Integer getBook_id() {
return book_id;
}
public void setBook_id(Integer book_id) {
this.book_id = book_id;
}
public Integer getOrder_id() {
return order_id;
}
public void setOrder_id(Integer order_id) {
this.order_id = order_id;
}
public String getOrderNo() {
return OrderNo;
}
public void setOrderNo(String orderNo) {
OrderNo = orderNo;
}
public String getBookName() {
return bookName;
}
public void setBookName(String bookName) {
this.bookName = bookName;
}
public BookOrder(Integer book_id, Integer order_id, String bookName, String orderNo) {
super();
this.book_id = book_id;
this.order_id = order_id;
this.bookName = bookName;
OrderNo = orderNo;
}
public BookOrder() {
super();
}
@Override
public String toString() {
return "BookOrder [book_id=" + book_id + ", order_id=" + order_id + ", bookName=" + bookName + ", OrderNo="
+ OrderNo + "]";
}
}
*.hbm.xml
?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class table="bookorder" name="com.zking.eight.entity.BookOrder">
<composite-id>
<key-property name="book_id" type="java.lang.Integer" column="book_id"></key-property>
<key-property name="order_id" type="java.lang.Integer" column="order_id"></key-property>
</composite-id>
<property name="bookName" type="java.lang.String" column="book_name"></property>
<property name="OrderNo" type="java.lang.String" column="order_no"></property>
</class>
</hibernate-mapping>
配置hibernate.cfg.xml檔案
<mapping resource="com/zking/eight/entity/BookOrder.hbm.xml"/>
public List<BookOrder> list4(){
Session session = SessionFactoryUtils.getSession();
Transaction transaction = session.beginTransaction();
// Map<String, Object> map=new HashMap<String, Object>();
String hql="from BookOrder";
List list = session.createQuery(hql).list();
transaction.commit();
session.close();
return list;
}