最近使用spring data jpa做了兩個項目,對於動態查詢的不友好做了個類似hibernate的封裝,記錄也分享下
首先定義一個所有條件的容器,繼承Specification
- /**
- * 定義一個查詢條件容器
- * @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));
- }
- // 將所有條件用 and 聯合起來
- if (predicates.size() > 0) {
- return builder.and(predicates.toArray(new Predicate[predicates.size()]));
- }
- }
- return builder.conjunction();
- }
- /**
- * 增加簡單條件表達式
- * @Methods Name add
- * @Create In 2012-2-8 By lee
- * @param expression0 void
- */
- public void add(Criterion criterion){
- if(criterion!=null){
- criterions.add(criterion);
- }
- }
- }
然后是各種條件組裝類,我首先做了一個接口來包裝各種條件
- /**
- * 條件接口
- * 用戶提供條件表達式接口
- * @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);
- }
然后是針對不同類型條件處理的實現
一個是簡單比較類型的處理
- /**
- * 簡單條件表達式
- * @author lee
- *
- */
- public class SimpleExpression implements Criterion{
- private String fieldName; //屬性名
- private Object value; //對應值
- private Operator operator; //計算符
- 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;
- }
- }
- }
一個邏輯條件計算實現
- /**
- * 邏輯條件表達式 用於復雜條件時使用,如但屬性多對應值的OR查詢等
- * @author lee
- *
- */
- public class LogicalExpression implements Criterion {
- private Criterion[] criterion; // 邏輯表達式中包含的表達式
- private Operator operator; //計算符
- 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;
- }
- }
- }
添加一個組裝工廠類
- /**
- * 條件構造器
- * 用於創建條件表達式
- * @Class Name Restrictions
- * @Author lee
- */
- public class Restrictions {
- /**
- * 等於
- * @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);
- }
- /**
- * 不等於
- * @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;
- }
- /**
- * 大於
- * @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);
- }
- /**
- * 小於
- * @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);
- }
- /**
- * 大於等於
- * @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);
- }
- /**
- * 小於等於
- * @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);
- }
- /**
- * 並且
- * @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);
- }
- /**
- * 包含於
- * @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);
其中eventDao為繼承JpaSpecificationExecutor的接口類
原文:http://lee1177.iteye.com/blog/1994295