/** * 定义一个查询条件容器 * @author lee * * @param <T> */ public class Criteria<T> implements Specification<T>{ private List<Criterion> criterions = new ArrayList<Criterion>(); public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder builder) { if (!criterions.isEmpty()) { List<Predicate> predicates = new ArrayList<Predicate>(); for(Criterion c : criterions){ predicates.add(c.toPredicate(root, query,builder)); } // 将所有条件用 and 联合起来 if (predicates.size() > 0) { return builder.and(predicates.toArray(new Predicate[predicates.size()])); } } return builder.conjunction(); } /** * 增加简单条件表达式 * @Methods Name add * @Create In 2012-2-8 By lee * @param expression0 void */ public void add(Criterion criterion){ if(criterion!=null){ criterions.add(criterion); } } }
然后是各种条件组装类，我首先做了一个接口来包装各种条件
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/** * 条件接口 * 用户提供条件表达式接口 * @Class Name Criterion * @Author lee * @Create In 2012-2-8 */ public interface Criterion { public enum Operator { EQ, NE, LIKE, GT, LT, GTE, LTE, AND, OR } public Predicate toPredicate(Root<?> root, CriteriaQuery<?> query, CriteriaBuilder builder); }
然后是针对不同类型条件处理的实现
一个是简单比较类型的处理
/** * 简单条件表达式 * @author lee * */ public class SimpleExpression implements Criterion{ private String fieldName; //属性名 private Object value; //对应值 private Operator operator; //计算符 protected SimpleExpression(String fieldName, Object value, Operator operator) { this.fieldName = fieldName; this.value = value; this.operator = operator; } public String getFieldName() { return fieldName; } public Object getValue() { return value; } public Operator getOperator() { return operator; } @SuppressWarnings({ "rawtypes", "unchecked" }) public Predicate toPredicate(Root<?> root, CriteriaQuery<?> query, CriteriaBuilder builder) { Path expression = null; if(fieldName.contains(".")){ String[] names = StringUtils.split(fieldName, "."); expression = root.get(names[0]); for (int i = 1; i < names.length; i++) { expression = expression.get(names[i]); } }else{ expression = root.get(fieldName); } switch (operator) { case EQ: return builder.equal(expression, value); case NE: return builder.notEqual(expression, value); case LIKE: return builder.like((Expression<String>) expression, "%" + value + "%"); case LT: return builder.lessThan(expression, (Comparable) value); case GT: return builder.greaterThan(expression, (Comparable) value); case LTE: return builder.lessThanOrEqualTo(expression, (Comparable) value); case GTE: return builder.greaterThanOrEqualTo(expression, (Comparable) value); default: return null; } } }
一个逻辑条件计算实现
/** * 逻辑条件表达式 用于复杂条件时使用，如但属性多对应值的OR查询等 * @author lee * */ public class LogicalExpression implements Criterion { private Criterion[] criterion; // 逻辑表达式中包含的表达式 private Operator operator; //计算符 public LogicalExpression(Criterion[] criterions, Operator operator) { this.criterion = criterions; this.operator = operator; } public Predicate toPredicate(Root<?> root, CriteriaQuery<?> query, CriteriaBuilder builder) { List<Predicate> predicates = new ArrayList<Predicate>(); for(int i=0;i<this.criterion.length;i++){ predicates.add(this.criterion[i].toPredicate(root, query, builder)); } switch (operator) { case OR: return builder.or(predicates.toArray(new Predicate[predicates.size()])); default: return null; } } }
添加一个组装工厂类
/** * 条件构造器 * 用于创建条件表达式 * @Class Name Restrictions * @Author lee */ public class Restrictions { /** * 等于 * @param fieldName * @param value * @param ignoreNull * @return */ public static SimpleExpression eq(String fieldName, Object value, boolean ignoreNull) { if(StringUtils.isEmpty(value))return null; return new SimpleExpression (fieldName, value, Operator.EQ); } /** * 不等于 * @param fieldName * @param value * @param ignoreNull * @return */ public static SimpleExpression ne(String fieldName, Object value, boolean ignoreNull) { if(StringUtils.isEmpty(value))return null; return new SimpleExpression (fieldName, value, Operator.NE); } /** * 模糊匹配 * @param fieldName * @param value * @param ignoreNull * @return */ public static SimpleExpression like(String fieldName, String value, boolean ignoreNull) { if(StringUtils.isEmpty(value))return null; return new SimpleExpression (fieldName, value, Operator.LIKE); } /** * * @param fieldName * @param value * @param matchMode * @param ignoreNull * @return */ public static SimpleExpression like(String fieldName, String value, MatchMode matchMode, boolean ignoreNull) { if(StringUtils.isEmpty(value))return null; return null; } /** * 大于 * @param fieldName * @param value * @param ignoreNull * @return */ public static SimpleExpression gt(String fieldName, Object value, boolean ignoreNull) { if(StringUtils.isEmpty(value))return null; return new SimpleExpression (fieldName, value, Operator.GT); } /** * 小于 * @param fieldName * @param value * @param ignoreNull * @return */ public static SimpleExpression lt(String fieldName, Object value, boolean ignoreNull) { if(StringUtils.isEmpty(value))return null; return new SimpleExpression (fieldName, value, Operator.LT); } /** * 大于等于 * @param fieldName * @param value * @param ignoreNull * @return */ public static SimpleExpression lte(String fieldName, Object value, boolean ignoreNull) { if(StringUtils.isEmpty(value))return null; return new SimpleExpression (fieldName, value, Operator.GTE); } /** * 小于等于 * @param fieldName * @param value * @param ignoreNull * @return */ public static SimpleExpression gte(String fieldName, Object value, boolean ignoreNull) { if(StringUtils.isEmpty(value))return null; return new SimpleExpression (fieldName, value, Operator.LTE); } /** * 并且 * @param criterions * @return */ public static LogicalExpression and(Criterion... criterions){ return new LogicalExpression(criterions, Operator.AND); } /** * 或者 * @param criterions * @return */ public static LogicalExpression or(Criterion... criterions){ return new LogicalExpression(criterions, Operator.OR); } /** * 包含于 * @param fieldName * @param value * @return */ @SuppressWarnings("rawtypes") public static LogicalExpression in(String fieldName, Collection value, boolean ignoreNull) { if(ignoreNull&&(value==null||value.isEmpty())){ return null; } SimpleExpression[] ses = new SimpleExpression[value.size()]; int i=0; for(Object obj : value){ ses[i]=new SimpleExpression(fieldName,obj,Operator.EQ); i++; } return new LogicalExpression(ses,Operator.OR); } }
使用方法如下
Criteria<Event> c = new Criteria<Event>(); c.add(Restrictions.like("code", searchParam.getCode(), true)); c.add(Restrictions.eq("level", searchParam.getLevel(), false)); c.add(Restrictions.eq("mainStatus", searchParam.getMainStatus(), true)); c.add(Restrictions.eq("flowStatus", searchParam.getFlowStatus(), true)); c.add(Restrictions.eq("createUser.userName", searchParam.getCreateUser(), true)); c.add(Restrictions.lte("submitTime", searchParam.getStartSubmitTime(), true)); c.add(Restrictions.gte("submitTime", searchParam.getEndSubmitTime(), true)); c.add(Restrictions.eq("needFollow", searchParam.getIsfollow(), true)); c.add(Restrictions.ne("flowStatus", CaseConstants.CASE_STATUS_DRAFT, true)); c.add(Restrictions.in("solveTeam.code",teamCodes, true)); eventDao.findAll(c);