Spring Data Jpa之高级查询（jpa-spec插件）

<dependency>
  <groupId>com.github.wenhao</groupId>
  <artifactId>jpa-spec</artifactId>
  <version>3.1.1</version>
  <!-- 把所有依赖都过滤 -->
  <exclusions>
    <exclusion>
      <groupId>*</groupId>
      <artifactId>*</artifactId>
    </exclusion>
  </exclusions>
</dependency>

public abstract class BaseQuery {
    private int currentPage=1;
    private int currentSize=10;
    private boolean sort = true;
    private String sortByColumn;
    //写成抽象类，子类必须实现
    public abstract Specification getSpecification();
    //分页加排序
    public Pageable getPageable(){
        Pageable pageRequest =new PageRequest(currentPage, currentSize);
        if (sortByColumn!=null&&!"".equals(sortByColumn)){
            if (sort){
                Sort sort = new Sort(Sort.Direction.ASC,sortByColumn);
                pageRequest = new PageRequest(currentPage, currentSize,sort);
                return pageRequest;
            }
            Sort sort = new Sort(Sort.Direction.DESC,sortByColumn);
            pageRequest = new PageRequest(currentPage, currentSize,sort);
            return pageRequest;
        }
        return pageRequest;
    }
    //拿到排序
    public Sort getSort(){
        if (sortByColumn!=null&&!"".equals(sortByColumn)){
            if (sort){
                Sort sort = new Sort(Sort.Direction.ASC,sortByColumn);
                return sort;
            }
            Sort sort = new Sort(Sort.Direction.DESC,sortByColumn);
            return sort;
        }
        return null;
    }
    提供相应的getter,setter
}

public class EmployeeQuery extends BaseQuery{
    private String username;
    private String email;
    private Integer age;
    private Long departmentId;
    @Override
    public Specification getSpecification() {
        Specification<Employee> spec = Specifications.<Employee>and()
                .like(StringUtils.isNotBlank(username),"username", "%"+username+"%")
                .like(StringUtils.isNotBlank(email),"email", "%"+email+"%")
                .ge(age !=null,"age",age)
                .eq(departmentId!=null,"departmentId.id",departmentId)
                .build();
        return spec;
    }
    getter,setter
}