SSH动态查询具体实现之Dao

最新推荐文章于 2019-06-13 20:49:26 发布

转载最新推荐文章于 2019-06-13 20:49:26 发布 · 359 阅读

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本文介绍了一种使用Spring、Hibernate和Struts2框架进行动态查询的方法。通过传递不同的参数组合，可以实现灵活的数据筛选和分页展示。代码示例展示了如何构建HQL查询语句并执行查询。

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http://blog.youkuaiyun.com/qiyuexuelang/article/details/17420297

[java] view plain copy

package com.sxdf.manage.dao.impl;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.Resource;
import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.stereotype.Component;
import com.sxdf.manage.dao.SnippetDao;
@Component("snippetDao")
public class SnippetDaoImpl implements SnippetDao {
@Resource(name = "sessionFactory")
private SessionFactory hu;
//统计总数（你可以使用count(*),前提是使用另一个HQL语句）
public int count(final String hql, final Object[] param) {
int count = 0;
Session session = hu.getCurrentSession();
Query query = session.createQuery(hql);
if (param.length > 0) {
for (int i = 0; i < param.length; i++) {
query.setString(i, param[i].toString());
}
}
List list = query.list();
if (list.size() > 0) {
count = list.size();
}
return count;
}
//查找当前页数据
public List<?> findPublic(final String hql, final Object[] param,
final int start, final int limit) {
Session session = hu.getCurrentSession();
Query query = session.createQuery(hql);
if (param.length > 0) {
for (int i = 0; i < param.length; i++) {
query.setString(i, param[i].toString());
}
}
List<?> list = query.setFirstResult(start).setMaxResults(limit).list();
return list;
}
//得到后半段hql
public String getHQL(Object[][] ob, Object[][] like
,String[][] datetime
, String[] group,String[] asc, String[] desc) {
StringBuffer hql = new StringBuffer();
String ss = null;
if (null != ob) {
for (Object[] o : ob) {
// [key][value] name='value'
boolean b = ((null != o[1]) && (null != o[0])
&& (!"".equals(o[1].toString()))
&& (!"".equals(o[0].toString())));
if (b) {
hql.append("and j." + o[0] + " =? ");
}
}
}
if (null != like) {
for (Object[] l : like) {
// [key][value] name like '%value%'
boolean bl = ((null != l[1]) && (null != l[0])
&& (!"".equals(l[1].toString()))
&& (!"".equals(l[0].toString())));
if (bl) {
hql.append("and j." + l[0] + " LIKE? ");
}
}
}
//时间（模糊）
if (null != datetime) {
for (String[] d : datetime) {
// [key][value]
boolean bd = ((null != d[1]) && (null != d[0])
&& (!"".equals(d[1])) && (!"".equals(d[0]
.toString())));
if (bd) {
hql.append("and to_char(j."+ d[0] +",'yyyy-mm-dd')" + " LIKE ? ");
}
}
}
// 分组 group by [value]
if (null != group && group.length > 0) {
StringBuffer groupb = new StringBuffer();
for (String str1 : group) {
if (null != str1 && !"".equals(str1)) {
groupb.append("j." + str1 + " , ");
}
}
if (null != groupb && "".equals("")) {
hql.append("group by ");
hql.append(groupb.substring(0, groupb.lastIndexOf(",")));
}
}
// 升序//降序(先升后降) order by [value]
if (null != asc && asc.length > 0 || null != desc && desc.length > 0) {
String oy1 = null;
String oy2 = null;
// orderb.append("order by ");
if (null != asc && asc.length > 0) {
StringBuffer orderb1 = new StringBuffer();
for (String str2 : asc) {
if (null != str2 && !"".equals(str2)) {
orderb1.append("j." + str2 + " , ");
}
}
if (null != orderb1 && "".equals(orderb1)) {
oy1 = orderb1.substring(0, orderb1.lastIndexOf(","))
+ " asc ";
}
}
if (null != desc && desc.length > 0) {
StringBuffer orderb2 = new StringBuffer();
for (String str3 : desc) {
if (null != str3 && !"".equals(str3)) {
orderb2.append("j." + str3 + " , ");
}
}
if (null != orderb2 && !"".equals(orderb2)) {
oy2 = orderb2.substring(0, orderb2.lastIndexOf(","))
+ " desc ";
}
}
if ((null != oy2 && !"".equals(oy2))
|| (null != oy1 && !"".equals(oy1))) {
hql.append("order by ");
if (null != oy1 && !"".equals(oy1)) {
hql.append(oy1);
}
if ((null != oy2 && !"".equals(oy2))
&& (null != oy1 && !"".equals(oy1))) {
hql.append(" , ");
}
if (null != oy2 && !"".equals(oy2)) {
hql.append(oy2);
}
}
}
if (hql.toString().contains("and")) {
ss = hql.substring(4, hql.length());
}
return ss;
}
//选值（=、like）
public List<Object> getValue(Object[][] ob, Object[][] like,String[][] datetime) {
List<Object> list = new ArrayList<Object>();
if (null != ob) {
for (Object[] o : ob) {
// [key][value]
boolean b = ((null != o[1]) && (null != o[0])
&& (!"".equals(o[1].toString())) && (!"".equals(o[0]
.toString())));
if (b) {
list.add(o[1]);
}
}
}
if (null != like) {
for (Object[] l : like) {
// [key][value]
boolean bl = ((null != l[1]) && (null != l[0])
&& (!"".equals(l[1].toString())) && (!"".equals(l[0]
.toString())));
if (bl) {
list.add("%" + l[1] + "%");
}
}
}
//时间（模糊）
if (null != datetime) {
for (String[] d : datetime) {
// [key][value]
boolean bd = ((null != d[1]) && (null != d[0])
&& (!"".equals(d[1])) && (!"".equals(d[0]
.toString())));
if (bd) {
list.add("%" + d[1] + "%");
}
}
}
return list;
}
}

由于删掉一些其他无关的类方法，故可能存在一些无用的import引入，对代码无影响

总结一下：本文大量使用if-else的运用，大大降低阅读效果。如果大家有好的方法和建议，洗耳恭听。
对sessionFactory 使用注解，
其中本类所继承的SnippetDao为上一篇中特意介绍的Dao接口方法，详细说明请参考上文-- SSH动态查询具体实现之service
Action 调取示例：

首先引入SnippetService

[java] view plain copy

@Resource(name = "snippetServiceImpl")
private SnippetService ss;

接下来，在action方法利用本接口实现你想要的查询

[java] view plain copy

Object[][] aa1 =null;
Object[][] aa2 =null;
String[] group =null;
String[] asc =null;
String[] desc = null;;
ActionWriteUtil.writeStr(JsonUtil.getPurchaseJson((List<Purchase>)ss.search(Purchase.class, aa1,aa2 ,null,group,asc,desc,start, limit),
ss.count(Purchase.class, aa1,aa2,null,group,asc,desc)));