以前用jpa写了一个条件筛选的查询数据如下,才知道那么渣渣,就是一个表,根据前端来筛选数据,写的如下
首先就是判断前端传来的参数就写了那么多,现在才发现是渣渣中的渣渣,而且还费时,用criteria很快就搞定
首先创建类并实现Specification<T>接口
import java.util.ArrayList; import java.util.List; import javax.persistence.criteria.CriteriaBuilder; import javax.persistence.criteria.CriteriaQuery; import javax.persistence.criteria.Predicate; import javax.persistence.criteria.Root; import org.springframework.data.jpa.domain.Specification; public class ExpandCriteria<T> implements Specification<T>{ private List<ExpandCriterion> criterions = new ArrayList<ExpandCriterion>(); public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder builder) { if (!criterions.isEmpty()) { List<Predicate> predicates = new ArrayList<Predicate>(); for(ExpandCriterion 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(ExpandCriterion criterion){ if(criterion!=null){ criterions.add(criterion); } } public static void main(String[] args) { //使用示例Demo // Criteria<Entity> c = new Criteria<Entity>(); // 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", searchParam.getMainStatus() true)); // c.add(Restrictions.in("solveTeam.code",teamCodes, true)); // repository.findAll(c); } }
新建ExpandCriterion接口
import javax.persistence.criteria.CriteriaBuilder; import javax.persistence.criteria.CriteriaQuery; import javax.persistence.criteria.Predicate; import javax.persistence.criteria.Root; public interface ExpandCriterion { public enum Operator { EQ, NE, LIKE, GT, LT, GTE, LTE, AND, OR } public Predicate toPredicate(Root<?> root, CriteriaQuery<?> query, CriteriaBuilder builder); }
新建Restrictions.java
import java.util.Collection; import org.springframework.util.StringUtils; import com.sll.iot.dao.base.criteria.ExpandCriterion.Operator; 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); } /** * 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(ExpandCriterion... criterions){ return new LogicalExpression(criterions, Operator.AND); } /** * 或者 * @param criterions * @return */ public static LogicalExpression or(ExpandCriterion... 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); }
新建SimpleExpression.java
import javax.persistence.criteria.CriteriaBuilder; import javax.persistence.criteria.CriteriaQuery; import javax.persistence.criteria.Expression; import javax.persistence.criteria.Path; import javax.persistence.criteria.Predicate; import javax.persistence.criteria.Root; public class SimpleExpression implements ExpandCriterion{ 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 = fieldName.split("."); 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; } } }
LogicalExpression.java
import java.util.ArrayList; import java.util.List; import javax.persistence.criteria.CriteriaBuilder; import javax.persistence.criteria.CriteriaQuery; import javax.persistence.criteria.Predicate; import javax.persistence.criteria.Root; public class LogicalExpression implements ExpandCriterion { private ExpandCriterion[] criterion; // 逻辑表达式中包含的表达式 private Operator operator; //计算符 public LogicalExpression(ExpandCriterion[] 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; } } }
使用criteria前提是dao接口必须实现JpaSpecificationExecutor<T>接口
改造如下
//条件查询 @Override public Paging<Channel> query(Paging<Channel> paging,String channelName,String operator) { Pageable pageReq = new PageRequest(paging.getCurrentPage()-1, paging.getPageSize()); Page<Channel> pageChanel=null; ExpandCriteria<Channel> criteria = new ExpandCriteria<Channel>(); if(StringUtil.isNotEmpty(channelName)){ criteria.add(Restrictions.like("name", channelName, false)); } if(StringUtil.isNotEmpty(operator)){ criteria.add(Restrictions.eq("operator",Operator.valueOf(operator), false)); } pageChanel=channelRepository.findAll(criteria, pageReq); if(pageChanel!=null){ paging.setTotalCount((int)pageChanel.getTotalElements()); paging.setData(pageChanel.getContent()); paging.setTotalPage(pageChanel.getTotalPages()); } return paging; }都不用在dao接口写什么东西
使用方法就是demo
public static void main(String[] args) { //使用示例Demo // Criteria<Entity> c = new Criteria<Entity>(); // 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", searchParam.getMainStatus() true)); // c.add(Restrictions.in("solveTeam.code",teamCodes, true)); // repository.findAll(c); }