spring boot jpa
使用方法：
将对应的model类注入即可
// fixed parameter type
private Specification<TargetModel> findByConditionSpecification(TargetModel formalParameter) {
return new Specification<TargetModel>() {
// fixed parameter type
@Override
public Predicate toPredicate(Root<TargetModel> root, CriteriaQuery<?> query,
CriteriaBuilder criteriaBuilder) {
List<Predicate> predicates = new ArrayList<Predicate>();
// fixed parameter type
Class clsEmployeeBase = TargetServiceImpl.class;
Method[] methods = clsEmployeeBase.getDeclaredMethods();
try {
for (Method method : methods) {
if (method.getName().equals("findByConditionSpecification")) {
Class clsEmployee = formalParameter.getClass();
Field[] fields = clsEmployee.getDeclaredFields();
for (Field field : fields) {
field.setAccessible(true);
if (!"serialVersionUID".equals(field.getName()) && field.get(formalParameter) != null) {
switch (field.getName()) {
case "id": {
// TODO fixed parameter,formal patameter primary key
TargetIdentity id = (TargetIdentity) field.get(formalParameter);
Field[] idFields = id.getClass().getDeclaredFields();
for (Field idField : idFields) {
idField.setAccessible(true);
if (!"serialVersionUID".equals(idField.getName())
&& idField.get(id) != null) {
String paramType = String.valueOf(idField.getType()).split(" ")[1];
switch (paramType) {
case "java.lang.String": {
String[] strs = String.valueOf(idField.get(id)).split(",");
Expression<String> express = root.get("id").get(idField.getName());
CriteriaBuilder.In<String> in = criteriaBuilder.in(express);
Arrays.asList(strs).forEach(n -> {
in.value(n);
});
predicates.add(in);
break;
}
case "java.util.Date": {
if (idField.getName().contains("start")) {
Expression<Date> express = root.get("id")
.get(idField.getName());
predicates.add(criteriaBuilder.greaterThanOrEqualTo(express,
(Date) (idField.get(id))));
break;
}
if (idField.getName().contains("end")) {
Expression<Date> express = root.get("id")
.get(idField.getName());
predicates.add(criteriaBuilder.lessThanOrEqualTo(express,
(Date) (idField.get(id))));
break;
}
}
default: {
Expression express = root.get("id").get(idField.getName());
predicates.add(criteriaBuilder.equal(express, idField.get(id)));
break;
}
}
}
}
break;
}
// 非联合主键
default: {
String paramType = String.valueOf(field.getType()).split(" ")[1];
switch (paramType) {
case "java.lang.String": {
String[] strs = String.valueOf(field.get(formalParameter)).split(",");
Expression<String> express = root.get(field.getName());
CriteriaBuilder.In<String> in = criteriaBuilder.in(express);
Arrays.asList(strs).forEach(n -> {
in.value(n);
});
predicates.add(in);
break;
}
case "java.util.Date": {
if (field.getName().contains("start")) {
Expression<Date> express = root.get(field.getName());
predicates.add(criteriaBuilder.greaterThanOrEqualTo(express,
(Date) (field.get(formalParameter))));
break;
}
if (field.getName().contains("end")) {
Expression<Date> express = root.get(field.getName());
predicates.add(criteriaBuilder.lessThanOrEqualTo(express,
(Date) (field.get(formalParameter))));
break;
}
}
default: {
Expression express = root.get(field.getName());
predicates.add(criteriaBuilder.equal(express, field.get(formalParameter)));
break;
}
}
break;
}
}
}
}
}
}
} catch (Exception e) {
// TODO: handle exception
}
query.where(predicates.toArray(new Predicate[predicates.size()]));
return query.getRestriction();
}
};
}