HQL的通用分頁
阿新 • • 發佈：2018-12-18
PageBean:
package com.zking.hibernate.util; import java.util.Map; import javax.servlet.http.HttpServletRequest; /** * 分頁工具類 * */ public class PageBean { private int page = 1;// 頁碼 private int rows = 2;// 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 + "]"; } }
StringUtils:
package com.zking.hibernate.util; 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); } }
BaseDao:
package com.zking.hibernate.dao; import java.util.List; import java.util.Map; import java.util.Map.Entry; import org.hibernate.Session; import org.hibernate.mapping.Collection; import org.hibernate.query.Query; import com.zking.hibernate.util.PageBean; public class BaseDao { private void setparameter(Query query, Map<String, Object> map) { if (null == map || map.size() == 0) { return; } // 給query賦值 Object value = null; for (Entry<String, Object> entry : map.entrySet()) { value = entry.getValue();// 賦值給value if (value instanceof Collection) { query.setParameterList(entry.getKey(), (java.util.Collection) value); } else if (value instanceof Object[]) { query.setParameterList(entry.getKey(), (Object[]) value); } else { query.setParameter(entry.getKey(), value); } } } private String getCountHql(String hql) { int index = hql.toUpperCase().indexOf("FROM");// 擷取from後面的sql語句 return "select count(*) " + hql.substring(index);// 查詢總數 } public List executeQuery(String hql, PageBean pageBean, Session session, Map<String, Object> map) { if (null != pageBean && pageBean.isPagination()) { String countHql = getCountHql(hql); Query counQuery = session.createQuery(countHql); this.setparameter(counQuery, map); String total = counQuery.getSingleResult().toString(); pageBean.setTotal(total); Query pageQuery = session.createQuery(hql);//每有分頁的 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(); } } }
Book實體類
package com.zking.hibernate.etity;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;
public class Book implements Serializable {
/**
*/
private static final long serialVersionUID = -3143423339101308878L;
private Integer book_id;
private String book_name;
private Float book_price;
private Set<Category> categorys = new HashSet<>();
private Integer initcategorys;
@Override
public String toString() {
return "Book [book_id="+ book_id +",book_name="+ book_name +",book_price="+ book_price +",categorys="+ categorys +"]";
}
public Integer getBook_id() {
return book_id;
}
public void setBook_id(Integer book_id) {
this.book_id = book_id;
}
public String getBook_name() {
return book_name;
}
public void setBook_name(String book_name) {
this.book_name = book_name;
}
public Float getBook_price() {
return book_price;
}
public void setBook_price(Float book_price) {
this.book_price = book_price;
}
public Set<Category> getCategorys() {
return categorys;
}
public void setCategorys(Set<Category> categorys) {
this.categorys = categorys;
}
public Book() {
super();
}
public Integer getInitcategorys() {
return initcategorys;
}
public void setInitcategorys(Integer initcategorys) {
this.initcategorys = initcategorys;
}
public Book(Integer book_id, String book_name) {
super();
this.book_id = book_id;
this.book_name = book_name;
}
public Book(Integer book_id,String book_name,Float book_price,Set<Category> categorys) {
super();
this.book_id = book_id;
this.book_name = book_name;
this.book_price = book_price;
this.categorys = categorys;
}
}
Book.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 name="com.zking.hibernate.etity.Book" table="t_hibernate_book">
<id name="book_id" type="java.lang.Integer" column="book_id">
<generator class="increment" />
</id>
<property name="book_name" type="java.lang.String" column="book_name"></property>
<property name="book_price" type="java.lang.Float" column="price"></property>
</class>
</hibernate-mapping>
BookDao:
package com.zking.hibernate.dao;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.query.Query;
import com.zking.hibernate.etity.Book;
import com.zking.hibernate.util.HibernateUtil;
import com.zking.hibernate.util.PageBean;
import com.zking.hibernate.util.StringUtils;
public class BookDao1 extends BaseDao{
public List<Book> list1(Book book,PageBean pageBean){
Session session = HibernateUtil.openSession();
Transaction transaction = session.beginTransaction();
Map<String, Object> map = new HashMap<>();
StringBuffer hql = new StringBuffer("from Book where 1=1");//初始化程式碼
if (StringUtils.isNotBlank(book.getBook_name())) {//名字不為空就拼接hql語句
hql.append(" and book_name like :bookname");
map.put("bookname", "%"+book.getBook_name()+"%");
}
// super.executeQuery(hql, pageBean, session, map);
// return list;
return null;
}
public List<Book> list2(Book book,PageBean pageBean){
Session session = HibernateUtil.openSession();
Transaction transaction = session.beginTransaction();
Map<String, Object> map = new HashMap<>();
String hql = "from Book where 1=1";//初始化程式碼
if (StringUtils.isNotBlank(book.getBook_name())) {//名字不為空就拼接hql語句
hql+=" and book_name like :bookname";
map.put("bookname", "%"+book.getBook_name()+"%");
}
List list = super.executeQuery(hql, pageBean, session, map);
return list;
}
}
BoodTest測試類:
package com.zking.hibernate.test;
import java.util.List;
import org.junit.Test;
import com.zking.hibernate.dao.BookDao1;
import com.zking.hibernate.etity.Book;
import com.zking.hibernate.util.PageBean;
public class BookLike {
private BookDao1 bookDao = new BookDao1();
@Test
public void run1() {
Book book = new Book();
// book.setBook_name("西");
PageBean pageBean = new PageBean();
List<Book> list1 = this.bookDao.list2(book, pageBean);
for(Book b : list1) {
System.out.println(b);
}
}
}