jpa JpaRepository <S extends T> List<S> findAll(Example<S> var1); 条件查询同时分页查询具体怎么写？写个例子

您好！关于您的问题，您可以使用Spring Data JPA提供的Specification来实现条件查询，同时使用Pageable来实现分页查询，具体的实现可以参考以下代码示例：

import org.springframework.data.domain.Example;
import org.springframework.data.domain.ExampleMatcher;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.stereotype.Service;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import java.util.ArrayList;
import java.util.List;

@Service
public interface YourRepository extends JpaRepository<S, Long> {

    default Page<S> search(S example, int pageNum, int pageSize) {
        ExampleMatcher matcher = ExampleMatcher.matching()
            .withMatcher("field1", ExampleMatcher.GenericPropertyMatchers.contains())
            .withMatcher("field2", ExampleMatcher.GenericPropertyMatchers.contains())
            .withIgnorePaths("id", "field3"); // ignore id and field3

        Example<S> exampleFilter = Example.of(example, matcher);

        Specification<S> spec = new Specification<S>() {
            @Override
            public Predicate toPredicate(Root<S> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
                List<Predicate> predicates = new ArrayList<>();

                /* add your filters here */
                predicates.add(cb.equal(root.get("field4"), "value1"));
                predicates.add(cb.like(root.get("field5"), "value2%"));

                return cb.and(predicates.toArray(new Predicate[predicates.size()]));
            }
        };

        PageRequest pageRequest = PageRequest.of(pageNum, pageSize);

        return findAll(spec.and(exampleFilter), pageRequest);
    }
}

其中，`S`代表实体类型，`field1`到`field5`代表实体中的属性名，`value1`和`value2`代表你要匹配的值，`pageNum`和`pageSize`分别代表页码和每页显示的记录数。

希望这可以帮到您！如果您还有任何问题，请随时联系我。