项目中Hibernate中Criteria和Query查询和模式引用

 在项目中Hibernate中Criteria和Query查询，总是缺少不了一些列的判断等，无论数据类型是什么，这些是必须的，最终动态添加的也是的获取Criteria和Query组成的hql，于是公司兄弟将Criteria和Query进行了抽出封装，采用设计模式中Builder的模式将组成hql过程的判断进行封装组合，使大家在使用时减少了判断是否为空或者空字符串等，细细的相信其实这也是设计模式的一部分好处吧！

 

封装类如下：

public class DynamicQuery {    private StringBuilder hql = new StringBuilder();    public List<String> parameterNames = new ArrayList<String>();    public List<Object> parameterValues = new ArrayList<Object>();    public List<String> getParameterNames() {        return parameterNames;    }    public List<Object> getParameterValues() {        return parameterValues;    }    public DynamicQuery(String hql) {        this.hql.append(hql);    }    public DynamicQuery append(String hql) {        return append(hql, (String[]) null, (String[]) null);    }       public DynamicQuery appendIfTrue(String hql, boolean condition) {     if (condition) {      append(hql);     }     return this;    }    public DynamicQuery append(String hql, String[] names, Object[] values) {        this.hql.append(" ").append(hql);        if (names != null && names.length != 0) {            parameterNames.addAll(Arrays.asList(names));        }        if (values != null && values.length != 0) {            parameterValues.addAll(Arrays.asList(values));        }        return this;    }    public DynamicQuery append(String hql, List<String> names, List<Object> values){        this.hql.append(" ").append(hql);        if (names != null && !names.isEmpty()) {            parameterNames.addAll(names);        }        if (values != null && !values.isEmpty()) {            parameterValues.addAll(values);        }        return this;    }    public DynamicQuery append(String hql, String name, Object value) {        return append(hql, new String[]{name}, new Object[]{value});    }    public DynamicQuery appendIfNotNull(String hql, String name, Object value) {        if (value != null) {            return append(hql, name, value);        }        return this;    }    public DynamicQuery appendIfNotEmpty(String hql, String name, String value) {        if (StringUtils.isNotBlank(value)) {            return append(hql, name, StringUtils.trim(value));        }        return this;    }       public DynamicQuery appendIfNotEmpty(String hql, String name, Collection<?> collection) {     if (CollectionUtils.isNotEmpty(collection)) {      return append(hql, name, collection);     }     return this;    }       public DynamicQuery appendLikeIfNotEmpty(String hql, String name, String value) {     return appendLikeIfNotEmpty(hql, name, value, MatchMode.ANYWHERE);    }       public DynamicQuery appendLikeIfNotNull(String hql,String name, Long value){     if(null != value){      return append(hql,name,value);     }     return this;    }       public DynamicQuery appendLikeIfNotEmpty(String hql, String name, String value, MatchMode matchMode) {     if (StringUtils.isNotBlank(value)) {      return appendLike(hql, name, value, matchMode);        }        return this;    }    private DynamicQuery appendLike(String hql, String name, String value, MatchMode matchMode) {  //TODO check me for some days  String regex = "(?i)\\slike\\s+:" + name + "(?=(\\s|\\)|$))";  Matcher matcher = Pattern.compile(regex).matcher(hql);  if (matcher.find()) {   int appendStart = matcher.end();   String front = StringUtils.substring(hql, 0, appendStart);   String back = StringUtils.substring(hql, appendStart);   String likeHql = front + " escape \'^\' " + back;   String likeValue = StringUtils.trim(value).replaceAll("%", "^%").replaceAll("_", "^_");   return append(likeHql, name, matchMode.toMatchString(likeValue));  }  throw new IllegalArgumentException("Like hql[" + hql + "] is error format."); } public DynamicQuery appendIfNotEmpty(String hql, String name, Object[] values) {     return appendIfNotEmpty(hql, name, values != null ? Arrays.asList(values) : Collections.EMPTY_LIST);    }    public String getQueryString() {        return this.hql.toString();    }       /**     * Apply the given name parameter to the given Query object.     *     * @param query the Query object     * @param name  the name of the parameter     * @param value the value of the parameter     */    @SuppressWarnings("unchecked")    private void setParameter(Query query, String name, Object value) {        if (value instanceof Collection) {            query.setParameterList(name, (Collection) value);        } else if (value instanceof Object[]) {            query.setParameterList(name, (Object[]) value);        } else {            query.setParameter(name, value);        }    }    public Query build(Session session) {        Query query = session.createQuery(this.getQueryString());        if (parameterNames != null && !parameterNames.isEmpty()) {            for (int i = 0; i < parameterNames.size(); i++) {                this.setParameter(query, parameterNames.get(i), this.parameterValues.get(i));            }        }        return query;    }}  使用代码如下： /**  * 分页查询时使用  *  * @param <T>  * @param paginater  * @param searchCondition  * @return  */ public <T> Paginater<T> paginate(Paginater<T> paginater, final ProductItemPriceCondition searchCondition) {  Sorter sorter = paginater.getSorter();  if (sorter.isEmpty()) {   sorter = new Sorter().asc("p.startDate");  }  LimitedList<T> limitedList = findByQuery(new QueryCreator() {   public Query createQuery(Session session) {    DynamicQuery dynamicQuery = new DynamicQuery("select distinct p from " + searchCondition.getForTypeName() + " p where (1 = 1) ");    dynamicQuery.appendIfNotNull(" and  p.startDate<=:endDate ", "endDate", searchCondition.getEndDate());    dynamicQuery.appendIfNotNull(" and p.endDate>=:startDate ", "startDate", searchCondition.getStartDate());    dynamicQuery.appendIfNotNull("and p.productId=:productId ", "productId", searchCondition.getProductId());    return dynamicQuery.build(session);   }  }, paginater.getLimit(), sorter);  return paginater.fromLimitedList(limitedList); }