Spring Data JPA Specification Query

 Private specification<vo> createspecification (final map<string, string> filterdata) throws Exception {        Final map<string, string> filteroperators = new hashmap<> ();                Final map<string, object> filterparams = new HashMap ();                Extractfilteroperatorsandparams (Filterdata, filteroperators, filterparams); Specification<vo> spec = new specification<vo> () {@Override public predicate Topredicat  E (root<vo> Root, criteriaquery<?> query, Criteriabuilder CB) {list<predicate> predicates                = new Arraylist<> ();                    For (map.entry<string, object> entry:filterParams.entrySet ()) {//get path to leaf node                    path<?> path = root;                    if (Attr_json_type.equals (Entry.getkey ())) {Predicates.add (Root.type (). In (Entry.getvalue ())); } else{for (String Pk:entry.getKey (). split ("\ \"))                        {Path = Path.get (PK); }//Create predicate Predicates.add (getfieldpredicate (CB, PATH, Filteropera                    Tors.get (Entry.getkey ()), Entry.getvalue ());            }} return Cb.and (Predicates.toarray (New Predicate[predicates.size ()));                } private predicate Getfieldpredicate (Criteriabuilder CB, path<?> Path, String operator, Object value) {                        if (op_equal.equals (operator)) {if (value instanceof Collection) {                    Return path.in ((Collection) value);                } return Cb.equal (path, value);                        } else if (Op_not.equals (operator)) {if (value instanceof Collection) { list<predicate> predicates = new Arraylist<> ();                        For (Object Val: (Collection) value) {Predicates.add (cb.notequal (Path, Val));                    } return Cb.and (Predicates.toarray (New Predicate[predicates.size ()));                    } else {return cb.notequal (path, value); }} else if (Op_like.equals (operator)) {return cb.like (path.as (string.cl                ), value.tostring ()); } else if (Op_notlike.equals (operator)) {return cb.notlike (path.as (string.class), value                . toString ()); } else if (Op_between.equals (operator)) {iterator<?> iter = (collection<?>                    ) value). iterator ();                    Object val1 = Iter.next (), val2 = Iter.next (); if (val1 instanceof Byte) {return Cb.between (path.as (byte.class), (Byte) val1, (byte) val2); } else if (Val1 instanceof short) {return Cb.between (path.as (Short.class), (Sho                    RT) Val1, (short) val2); } else if (Val1 instanceof Integer) {return Cb.between (path.as (Integer.class),                    (integer) val1, (integer) val2);  } else if (Val1 instanceof Long) {return Cb.between (path.as (Long.class), (Long)                    Val1, (Long) val2); } else if (Val1 instanceof Float) {return Cb.between (path.as (Float.class), (Flo                    at) Val1, (Float) val2); } else if (Val1 instanceof Double) {return Cb.between (path.as (Double.class), (D                    ouble) Val1, (Double) val2);                    } else {return null;     }} else {               try {Method m = null; if (op_gt.equals (operator)) {m = Cb.getclass (). GetMethod ("GreaterThan", Expression.class, Comp                        Arable.class); } else if (Op_ge.equals (operator)) {m = Cb.getclass (). GetMethod ("Greate                        Rthanorequalto ", Expression.class, Comparable.class); } else if (Op_lt.equals (operator)) {m = Cb.getclass (). GetMethod ("Lessth                        An ", Expression.class, Comparable.class); } else if (Op_le.equals (operator)) {m = Cb.getclass (). GetMethod ("Lessth                        Anorequalto ", Expression.class, Comparable.class);                                if (M! = null) {if (value instanceof Byte) { return (predicate) M.invoke (CB, Path.as (Byte.class), (Byte) value); } else if (value instanceof short) {return (predicate) M.invoke                            (CB, Path.as (Short.class), (short) value); } else if (value instanceof Integer) {return (predicate) m.invo                            Ke (CB, path.as (Integer.class), (Integer) value); } else if (value instanceof Long) {return (predicate) M.invoke (                            CB, Path.as (Long.class), (Long) value); } else if (value instanceof Float) {return (predicate) M.invoke                            (CB, Path.as (Float.class), (Float) value); } else if (value instanceof Double) {return (predicate) M.invok E (CB, PATH.AS (Double.class),(Double) value); }}} catch (Exception e) {throw new                    RuntimeException (e);                } return null;                }            }        };    return spec; }

Reference:

Http://docs.spring.io/spring-data/data-jpa/docs/1.0.x/api/org/springframework/data/jpa/domain/Specification.html

Http://docs.oracle.com/javaee/5/api/javax/persistence/package-summary.html

Http://wenku.baidu.com/view/190e385c3b3567ec102d8a40.html?re=view

Spring Data JPA Specification Query