hibernate的通用查询

package com.zking.util;

import org.hibernate.Session;
import org.hibernate.query.Query;

import java.util.Collection;
import java.util.List;
import java.util.Map;

/**

• hql的通用查询

• sql Pagebean Class clz

• 1.hql语句传过来拼接Countsql

• 2.给命名参数赋值

• 3.pageBean.settotal

• 4.查询你所需要的结果集
  /
  public class BaseDao {
  /*

  • 给命名参数赋值
  • @param query
  • @param map
    */
    private void setParameters(Query query, Map map) {
    if (map == null || map.size() == 0) {
    return;
    }
    Object value;
    for (Map.Entry 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);
    }
    }

  }

  /**

  • 拼装hql语句，Counthql
  • 用于查询符合记录的所有记录数
  • @param hql
  • @return
    /
    public String getCountSql(String hql) {
    int index = hql.toUpperCase().indexOf(“FROM”);
    return "select count() " + hql.substring(index);
    }

  /**

  • 通用查询
  • @param session
  • @param hql
  • @param map 含有命名参数的集合
  • @param pageBean
  • @return
    */
    protected List executeQuery(Session session, String hql, Map map, PageBean pageBean) {
    if (pageBean != null && pageBean.isPagination()) {
    String countsql=getCountSql(hql);
    Query countquery=session.createQuery(countsql);
    this.setParameters(countquery,map);
    pageBean.setTotal(countquery.getSingleResult().toString());
    Query query = session.createQuery(hql);
    this.setParameters(query,map);
    query.setFirstResult(pageBean.getStartIndex());
    query.setMaxResults(pageBean.getRows());
    return query.list();
    } else {
    Query query = session.createQuery(hql);
    this.setParameters(query, map);
    return query.list();
    }
    }

}
此处使用到了Pagebean 一个分页的类 在这里也把代码贴出来

package com.zking.util;

import javax.servlet.http.HttpServletRequest;
import java.util.Map;

public class PageBean {
private int page = 1;// 页码

private int rows = 10;// 页大小

private int total = 0;// 总记录数

private boolean pagination = true;// 是否分页
private String url;
private Map parameterMap;//所有参数集合
/**
 *
 * @Title: setPageBean
 * @Description: (初始化对象的方法)
 * @param request
 * @return void
 */
public void   setPageBean(HttpServletRequest request) {
    this.page=request.getParameter("page")==null?1:Integer.parseInt(request.getParameter("page"));
    this.rows=request.getParameter("rows")==null?5:Integer.parseInt(request.getParameter("rows"));
    // 只有jsp页面上填写pagination=false才是不分页
    this.setPagination(!"false".equals(request.getParameter("pagination")));
    this.setParameterMap(request.getParameterMap());
    this.setUrl(request.getRequestURL().toString());
}
/**
 *
 * @Title: getMaxPages
 * @Description: (最大页码数)
 * @return
 * @return int
 */
public int getMaxPages() {
    return this.total%this.rows==0?this.total/this.rows:this.total/this.rows+1;
}
/**
 *
 * @Title: getNextPages
 * @Description: (下一页页码)
 * @return
 * @return int
 */
public int getNextPages() {
    return this.page0?this.page-1:1;
}

public String getUrl() {
    return url;
}

public void setUrl(String url) {
    this.url = url;
}

public Map getParameterMap() {
    return parameterMap;
}

public void setParameterMap(Map parameterMap) {
    this.parameterMap = parameterMap;
}

public PageBean() {
    super();
    // TODO Auto-generated constructor stub
}

public PageBean(int page, int rows, int total, boolean pagination) {
    super();
    this.page = page;
    this.rows = rows;
    this.total = total;
    this.pagination = pagination;
}

public int getPage() {
    return page;
}

public void setPage(int page) {
    this.page = page;
}

public int getRows() {
    return rows;
}

public void setRows(int rows) {
    this.rows = 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;
}

/**
 * 获得起始记录的下标
 *
 * @return
 */
public int getStartIndex() {
    return (this.page - 1) * this.rows;
}

@Override
public String toString() {
    return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination + "]";
}

}

作者：yjt520557
来源：CSDN
原文：https://blog.csdn.net/yjt520557/article/details/84672086
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