spring jpa 字段映射data jpa 能不能只返回一个字段的值,而不是整个对象

SpringDataJPA学习记录(三)--复杂查询的封装 - 简书
SpringDataJPA学习记录(三)--复杂查询的封装
SpringDataJPA学习记录(三)--复杂查询的封装
标签(空格分隔): springJPA
1.使用CriteriaBuilder构建JPQL
在UserRepositoryImpl中使用CriteriaBuilder实现根据id查询,下面是代码:
public void findById(Integer id){
//select u from User u where u.id = 1
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery&User& cq = cb.createQuery(User.class);
Root&User& root = cq.from(User.class); //from User
cq.select(root); //select * from User
javax.persistence.criteria.Predicate pre = cb.equal(root.get("id").as(Integer.class),id);//id=1
cq.where(pre);//where id=1
Query query = entityManager.createQuery(cq);//select u from User u where u.id = 1
System.out.println(query.getResultList());
条件复杂的话,则会显得很混乱.
个人认为,CriteriaQuery不适合用来复杂sql的查询实现,不过可以使用其对一些通用的sql查询封装到BaseDao中.具体封装接着往下看.
2.使用JpaSpecificationExecutor查询
该接口有如下方法,里面传入条件都是Specification,该接口会返回一个Predicate条件集合,因此就可以在这里封装.
public interface JpaSpecificationExecutor&T& {
T findOne(Specification&T& spec);
List&T& findAll(Specification&T& spec);
Page&T& findAll(Specification&T& spec, Pageable pageable);
List&T& findAll(Specification&T& spec, Sort sort);
long count(Specification&T& spec);
1.构造过滤条件集合
写法学习自shop++项目.Operator枚举类里面的operator属性为了构建原生sql使用
* @author Niu Li
import mons.lang3.builder.EqualsB
import mons.lang3.builder.HashCodeB
import java.io.S
* copy from shopXX
public class Filter implements Serializable {
private static final long serialVersionUID = -1065075L;
public enum Operator {
/** 等于 */
eq(" = "),
/** 不等于 */
ne(" != "),
/** 大于 */
gt(" & "),
/** 小于 */
lt(" & "),
/** 大于等于 */
ge(" &= "),
/** 小于等于 */
le(" &= "),
/** 类似 */
like(" like "),
/** 包含 */
in(" in "),
/** 为Null */
isNull(" is NULL "),
/** 不为Null */
isNotNull(" is not NULL ");
Operator(String operator) {
this.operator =
public String getOperator() {
public void setOperator(String operator) {
this.operator =
/** 默认是否忽略大小写 */
private static final boolean DEFAULT_IGNORE_CASE =
/** 属性 */
/** 运算符 */
private Filter.O
/** 是否忽略大小写 */
private Boolean ignoreCase = DEFAULT_IGNORE_CASE;
* 构造方法
public Filter() {
* 构造方法
* @param property
* @param operator
* @param value
public Filter(String property, Filter.Operator operator, Object value) {
this.property =
this.operator =
this.value =
* 构造方法
* @param property
* @param operator
* @param value
* @param ignoreCase
忽略大小写
public Filter(String property, Filter.Operator operator, Object value, boolean ignoreCase) {
this.property =
this.operator =
this.value =
this.ignoreCase = ignoreC
* 返回等于筛选
* @param property
* @param value
* @return 等于筛选
public static Filter eq(String property, Object value) {
return new Filter(property, Filter.Operator.eq, value);
* 返回等于筛选
* @param property
* @param value
* @param ignoreCase
忽略大小写
* @return 等于筛选
public static Filter eq(String property, Object value, boolean ignoreCase) {
return new Filter(property, Filter.Operator.eq, value, ignoreCase);
* 返回不等于筛选
* @param property
* @param value
* @return 不等于筛选
public static Filter ne(String property, Object value) {
return new Filter(property, Filter.Operator.ne, value);
* 返回不等于筛选
* @param property
* @param value
* @param ignoreCase
忽略大小写
* @return 不等于筛选
public static Filter ne(String property, Object value, boolean ignoreCase) {
return new Filter(property, Filter.Operator.ne, value, ignoreCase);
* 返回大于筛选
* @param property
* @param value
* @return 大于筛选
public static Filter gt(String property, Object value) {
return new Filter(property, Filter.Operator.gt, value);
* 返回小于筛选
* @param property
* @param value
* @return 小于筛选
public static Filter lt(String property, Object value) {
return new Filter(property, Filter.Operator.lt, value);
* 返回大于等于筛选
* @param property
* @param value
* @return 大于等于筛选
public static Filter ge(String property, Object value) {
return new Filter(property, Filter.Operator.ge, value);
* 返回小于等于筛选
* @param property
* @param value
* @return 小于等于筛选
public static Filter le(String property, Object value) {
return new Filter(property, Filter.Operator.le, value);
* 返回相似筛选
* @param property
* @param value
* @return 相似筛选
public static Filter like(String property, Object value) {
return new Filter(property, Filter.Operator.like, value);
* 返回包含筛选
* @param property
* @param value
* @return 包含筛选
public static Filter in(String property, Object value) {
return new Filter(property, Filter.Operator.in, value);
* 返回为Null筛选
* @param property
* @return 为Null筛选
public static Filter isNull(String property) {
return new Filter(property, Filter.Operator.isNull, null);
* 返回不为Null筛选
* @param property
* @return 不为Null筛选
public static Filter isNotNull(String property) {
return new Filter(property, Filter.Operator.isNotNull, null);
* 返回忽略大小写筛选
* @return 忽略大小写筛选
public Filter ignoreCase() {
this.ignoreCase =
* 获取属性
* @return 属性
public String getProperty() {
* 设置属性
* @param property
public void setProperty(String property) {
this.property =
* 获取运算符
* @return 运算符
public Filter.Operator getOperator() {
* 设置运算符
* @param operator
public void setOperator(Filter.Operator operator) {
this.operator =
* @return 值
public Object getValue() {
* @param value
public void setValue(Object value) {
this.value =
* 获取是否忽略大小写
* @return 是否忽略大小写
public Boolean getIgnoreCase() {
return ignoreC
* 设置是否忽略大小写
* @param ignoreCase
是否忽略大小写
public void setIgnoreCase(Boolean ignoreCase) {
this.ignoreCase = ignoreC
* 重写equals方法
* @param obj
* @return 是否相等
public boolean equals(Object obj) {
if (obj == null) {
if (getClass() != obj.getClass()) {
if (this == obj) {
Filter other = (Filter)
return new EqualsBuilder().append(getProperty(), other.getProperty()).append(getOperator(), other.getOperator()).append(getValue(), other.getValue()).isEquals();
* 重写hashCode方法
* @return HashCode
public int hashCode() {
return new HashCodeBuilder(17, 37).append(getProperty()).append(getOperator()).append(getValue()).toHashCode();
2.构造排序字段
import mons.lang3.builder.EqualsB
import mons.lang3.builder.HashCodeB
import java.io.S
* @author copy from shopxx
public class Order implements Serializable {
private static final long serialVersionUID = -7773232L;
public enum Direction {
/** 递增 */
/** 递减 */
/** 默认方向 */
private static final Order.Direction DEFAULT_DIRECTION = Order.Direction.
/** 属性 */
/** 方向 */
private Order.Direction direction = DEFAULT_DIRECTION;
public String toString() {
return property+" " + direction.name();
* 构造方法
public Order() {
* 构造方法
* @param property
* @param direction
public Order(String property, Order.Direction direction) {
this.property =
this.direction =
* 返回递增排序
* @param property
* @return 递增排序
public static Order asc(String property) {
return new Order(property, Order.Direction.asc);
* 返回递减排序
* @param property
* @return 递减排序
public static Order desc(String property) {
return new Order(property, Order.Direction.desc);
* 获取属性
* @return 属性
public String getProperty() {
* 设置属性
* @param property
public void setProperty(String property) {
this.property =
* 获取方向
* @return 方向
public Order.Direction getDirection() {
* 设置方向
* @param direction
public void setDirection(Order.Direction direction) {
this.direction =
* 重写equals方法
* @param obj
* @return 是否相等
public boolean equals(Object obj) {
if (obj == null) {
if (getClass() != obj.getClass()) {
if (this == obj) {
Order other = (Order)
return new EqualsBuilder().append(getProperty(), other.getProperty()).append(getDirection(), other.getDirection()).isEquals();
* 重写hashCode方法
* @return HashCode
public int hashCode() {
return new HashCodeBuilder(17, 37).append(getProperty()).append(getDirection()).toHashCode();
3.查询语句生成
3.1基本框架
* 封装查询条件的实体
* @author Niu Li
public class QueryParams&T& implements Specification&T& {
/** 属性分隔符 */
private static final String PROPERTY_SEPARATOR = ".";
private List&Filter& andFilters = new ArrayList&&();
private List&Filter& orFilters = new ArrayList&&();
* 排序属性
private List&Order& orders = new ArrayList&&();
* 获取Path
* @param path
* @param propertyPath
* @return Path
@SuppressWarnings("unchecked")
private &X& Path&X& getPath(Path&?& path, String propertyPath) {
if (path == null || StringUtils.isEmpty(propertyPath)) {
return (Path&X&)
String property = StringUtils.substringBefore(propertyPath, PROPERTY_SEPARATOR);
return getPath(path.get(property), StringUtils.substringAfter(propertyPath, PROPERTY_SEPARATOR));
3.2分析and条件:
* 转换为Predicate
* @param root
* @return Predicate
@SuppressWarnings("unchecked")
private Predicate toAndPredicate(Root&T& root,CriteriaBuilder criteriaBuilder) {
Predicate restrictions = criteriaBuilder.conjunction();
if (root == null || CollectionUtils.isEmpty(andFilters)) {
for (Filter filter : andFilters) {
if (filter == null) {
String property = filter.getProperty();
Filter.Operator operator = filter.getOperator();
Object value = filter.getValue();
Boolean ignoreCase = filter.getIgnoreCase();
Path&?& path = getPath(root, property);
if (path == null) {
//根据运算符生成相应条件
switch (operator) {
if (value != null) {
if (BooleanUtils.isTrue(ignoreCase) && String.class.isAssignableFrom(path.getJavaType()) && value instanceof String) {
restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.equal(criteriaBuilder.lower((Path&String&) path), ((String) value).toLowerCase()));
restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.equal(path, value));
restrictions = criteriaBuilder.and(restrictions, path.isNull());
if (value != null) {
if (BooleanUtils.isTrue(ignoreCase) && String.class.isAssignableFrom(path.getJavaType()) && value instanceof String) {
restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.notEqual(criteriaBuilder.lower((Path&String&) path), ((String) value).toLowerCase()));
restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.notEqual(path, value));
restrictions = criteriaBuilder.and(restrictions, path.isNotNull());
if (Number.class.isAssignableFrom(path.getJavaType()) && value instanceof Number) {
restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.gt((Path&Number&) path, (Number) value));
if (Number.class.isAssignableFrom(path.getJavaType()) && value instanceof Number) {
restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.lt((Path&Number&) path, (Number) value));
if (Number.class.isAssignableFrom(path.getJavaType()) && value instanceof Number) {
restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.ge((Path&Number&) path, (Number) value));
if (Number.class.isAssignableFrom(path.getJavaType()) && value instanceof Number) {
restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.le((Path&Number&) path, (Number) value));
case like:
if (String.class.isAssignableFrom(path.getJavaType()) && value instanceof String) {
if (BooleanUtils.isTrue(ignoreCase)) {
restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.like(criteriaBuilder.lower((Path&String&) path), ((String) value).toLowerCase()));
restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.like((Path&String&) path, (String) value));
restrictions = criteriaBuilder.and(restrictions, path.in(value));
case isNull:
restrictions = criteriaBuilder.and(restrictions, path.isNull());
case isNotNull:
restrictions = criteriaBuilder.and(restrictions, path.isNotNull());
3.3分析or条件:
把and中的and改为or即可
* 转换为Predicate
* @param root
* @return Predicate
@SuppressWarnings("unchecked")
private Predicate toOrPredicate(Root&T& root,CriteriaBuilder criteriaBuilder) {
Predicate restrictions = criteriaBuilder.disjunction();
if (root == null || CollectionUtils.isEmpty(andFilters)) {
for (Filter filter : orFilters) {
if (filter == null) {
String property = filter.getProperty();
Filter.Operator operator = filter.getOperator();
Object value = filter.getValue();
Boolean ignoreCase = filter.getIgnoreCase();
Path&?& path = getPath(root, property);
if (path == null) {
switch (operator) {
if (value != null) {
if (BooleanUtils.isTrue(ignoreCase) && String.class.isAssignableFrom(path.getJavaType()) && value instanceof String) {
restrictions = criteriaBuilder.or(restrictions, criteriaBuilder.equal(criteriaBuilder.lower((Path&String&) path), ((String) value).toLowerCase()));
restrictions = criteriaBuilder.or(restrictions, criteriaBuilder.equal(path, value));
restrictions = criteriaBuilder.or(restrictions, path.isNull());
if (value != null) {
if (BooleanUtils.isTrue(ignoreCase) && String.class.isAssignableFrom(path.getJavaType()) && value instanceof String) {
restrictions = criteriaBuilder.or(restrictions, criteriaBuilder.notEqual(criteriaBuilder.lower((Path&String&) path), ((String) value).toLowerCase()));
restrictions = criteriaBuilder.or(restrictions, criteriaBuilder.notEqual(path, value));
restrictions = criteriaBuilder.or(restrictions, path.isNotNull());
if (Number.class.isAssignableFrom(path.getJavaType()) && value instanceof Number) {
restrictions = criteriaBuilder.or(restrictions, criteriaBuilder.gt((Path&Number&) path, (Number) value));
if (Number.class.isAssignableFrom(path.getJavaType()) && value instanceof Number) {
restrictions = criteriaBuilder.or(restrictions, criteriaBuilder.lt((Path&Number&) path, (Number) value));
if (Number.class.isAssignableFrom(path.getJavaType()) && value instanceof Number) {
restrictions = criteriaBuilder.or(restrictions, criteriaBuilder.ge((Path&Number&) path, (Number) value));
if (Number.class.isAssignableFrom(path.getJavaType()) && value instanceof Number) {
restrictions = criteriaBuilder.or(restrictions, criteriaBuilder.le((Path&Number&) path, (Number) value));
case like:
if (String.class.isAssignableFrom(path.getJavaType()) && value instanceof String) {
if (BooleanUtils.isTrue(ignoreCase)) {
restrictions = criteriaBuilder.or(restrictions, criteriaBuilder.like(criteriaBuilder.lower((Path&String&) path), ((String) value).toLowerCase()));
restrictions = criteriaBuilder.or(restrictions, criteriaBuilder.like((Path&String&) path, (String) value));
restrictions = criteriaBuilder.or(restrictions, path.in(value));
case isNull:
restrictions = criteriaBuilder.or(restrictions, path.isNull());
case isNotNull:
restrictions = criteriaBuilder.or(restrictions, path.isNotNull());
3.4分析排序条件:
* 转换为Order
* @param root
* @return Order
private List&javax.persistence.criteria.Order& toOrders(Root&T& root,CriteriaBuilder criteriaBuilder) {
List&javax.persistence.criteria.Order& orderList = new ArrayList&javax.persistence.criteria.Order&();
if (root == null || CollectionUtils.isEmpty(orders)) {
return orderL
for (Order order : orders) {
if (order == null) {
String property = order.getProperty();
Order.Direction direction = order.getDirection();
Path&?& path = getPath(root, property);
if (path == null || direction == null) {
switch (direction) {
orderList.add(criteriaBuilder.asc(path));
case desc:
orderList.add(criteriaBuilder.desc(path));
return orderL
最后在toPredicate方法中构造最终条件
* 生成条件的
* @param root 该对象的封装
* @param query 查询构建器
* @param cb 构建器
* @return 条件集合
public Predicate toPredicate(Root&T& root, CriteriaQuery&?& query, CriteriaBuilder cb) {
//如果无or条件,toOrPredicate会自带一个 or 1=1,前面用and的话则变为and 1=1造成错误,所以这里判断下
//这个貌似和版本有关,公司线上版本出现这个问题,本地测试没问题
Predicate restrictions = cb.and(toAndPredicate(root,cb));
if(!orders.isEmpty()){
restrictions = cb.and(restrictions,toOrPredicate(root,cb));}
query.orderBy(toOrders(root,cb));
加上方便的链式调用方法
* 添加一个and条件
* @param filter 该条件
* @return 链式调用
QueryParams and(Filter filter){
this.andFilters.add(filter);
* 添加多个and条件
* @param filter 该条件
* @return 链式调用
QueryParams and(Filter ...filter){
this.andFilters.addAll(Arrays.asList(filter));
* 添加一个or条件
* @param filter 该条件
* @return 链式调用
QueryParams or(Filter filter){
this.orFilters.add(filter);
* 添加多个or条件
* @param filter 该条件
* @return 链式调用
QueryParams or(Filter ...filter){
this.orFilters.addAll(Arrays.asList(filter));
* 升序字段
* @param property 该字段对应变量名
* @return 链式调用
QueryParams orderASC(String property){
this.orders.add(Order.asc(property));
* 降序字段
* @param property 该字段对应变量名
* @return 链式调用
QueryParams orderDESC(String property){
this.orders.add(Order.desc(property));
* 清除所有条件
* @return 该实例
public QueryParams clearAll(){
if (!this.andFilters.isEmpty()) this.andFilters.clear();
if (!this.orFilters.isEmpty()) this.orFilters.clear();
if (!this.orders.isEmpty()) this.orders.clear();
* 清除and条件
* @return 该实例
public QueryParams clearAnd(){
if (!this.andFilters.isEmpty()) this.andFilters.clear();
* 清除or条件
* @return 该实例
public QueryParams clearOr(){
if (!this.orFilters.isEmpty()) this.andFilters.clear();
* 清除order条件
* @return 该实例
public QueryParams clearOrder(){
if (!this.orders.isEmpty()) this.orders.clear();
//省略get和set方法
首先让PcardOrderRepository接口继承加上JpaSpecificationExecutor
public interface PcardOrderRepository extends JpaRepository&PcardOrder,String&
,PcardOrderRepositoryCustom,JpaSpecificationExecutor&PcardOrder& {
编写测试代码,这个使用的是CriteriaBuilder构建查询的,所以查询字段都是JPQL字段,并不是原生sql
QueryParams&PcardOrder& queryParams = new QueryParams&&();
//使用Specification条件查询,使用JPQL字段查询
queryParams
.and(Filter.eq("acctId","7371041"),Filter.ne("orderAmt",0L),
Filter.eq("orderRespCd","00"))
.or(Filter.eq("orderTypeId","A003"),Filter.eq("orderTypeId","A007"),
Filter.eq("orderTypeId","A021"),Filter.eq("orderTypeId","A018"))
.orderDESC("createTime");
Page&PcardOrder& JPQLlist = pcardOrderRepository.findAll(queryParams,new PageRequest(0,2));
//构造出来的条件
and pcardorder0_.acct_id=?
and pcardorder0_.order_amt&&0
and pcardorder0_.order_resp_cd=?
or pcardorder0_.order_type_id=?
or pcardorder0_.order_type_id=?
or pcardorder0_.order_type_id=?
or pcardorder0_.order_type_id=?
pcardorder0_.create_time desc limit ?
3.原生sql查询
还是利用上面的Filter,具体还是遍历+拼接,示例中我卸载了公共方法中,需要使用的Impl直接extends即可.
1.解析条件
解析条件实际上就是拼接sql,代码很简单.
* 公共方法的repository
* @author Niu Li
@NoRepositoryBean
public class BaseRepository {
private static Logger logger = LoggerFactory.getLogger(BaseRepository.class);
* 分析查询参数,并且合并到sql语句中
* @param sql JPQL查询语句
* @param params 查询参数
* @return 参数对应的value
@SuppressWarnings("Unchecked")
protected List&Object& analysisQueryParams(StringBuilder sql, QueryParams&?& params){
List&String& strList = new ArrayList&&();
List&Object& valueList = new ArrayList&&();
int i = 1;
//分析or条件
for (Filter filter : params.getOrFilters()) {
if (filter.getValue() != null){
strList.add(filter.getProperty()+" " + filter.getOperator().getOperator()+" ?" + (i++));
valueList.add(filter.getValue());
strList.add(filter.getProperty()+" " + filter.getOperator().getOperator()+" ");
if (!strList.isEmpty()){
sql.append(" and ").append("( ").append(StringUtils.join(strList," or ")).append(" )");
strList.clear();
//分析and条件
for (Filter filter : params.getAndFilters()) {
if (filter.getValue() != null){
strList.add(filter.getProperty()+" " + filter.getOperator().getOperator()+" ?" + (i++));
valueList.add(filter.getValue());
strList.add(filter.getProperty()+" " + filter.getOperator().getOperator()+" ");
sql.append(" and ").append(StringUtils.join(strList," and "));
//分析排序字段
if (!params.getOrders().isEmpty()){
sql.append(" order by ");
sql.append(StringUtils.join(params.getOrders(),","));
logger.debug("解析后的sql:"+sql.toString());
logger.debug("对应的值为:"+valueList);
return valueL
在自定义接口中加入方法
* @author Niu Li
public interface PcardOrderRepositoryCustom {
List findByQueryParam(QueryParams queryParams, Pageable pageable);
然后实现类中需要写部分sql
* @author Niu Li
@NoRepositoryBean
public class PcardOrderRepositoryImpl extends BaseRepository implements PcardOrderRepositoryCustom {
@PersistenceContext
private EntityManager entityM
public List findByQueryParam(QueryParams queryParams, Pageable pageable) {
StringBuilder sql = new StringBuilder("select * from tbl_pcard_order where 1=1 ");
List values = analysisQueryParams(sql,queryParams);
Query query = entityManager.createNativeQuery(sql.toString());
for (int i = 0; i & values.size(); i++) {
query.setParameter(i+1,values.get(i));
query.setFirstResult(pageable.getOffset());
query.setMaxResults(pageable.getPageSize());
return query.getResultList();
//使用原生sql查询,注意这里使用原生sql字段,并非JPQL字段,
//本质是根据BaseRepository.analysisQueryParams 来拼接条件,可以根据自己的需求更改
queryParams.clearAll()
.and(Filter.eq("acct_id","7371041"),Filter.ne("order_amt",0L),
Filter.eq("order_resp_cd","00"))
.or(Filter.eq("order_type_id","A003"),Filter.eq("order_type_id","A007"),
Filter.eq("order_type_id","A021"),Filter.eq("order_type_id","A018"))
.orderDESC("create_time");
List nativeSqlList = pcardOrderRepository.findByQueryParam(queryParams,new PageRequest(0,2));
//构造出来的sql
order_type_id
or order_type_id
or order_type_id
or order_type_id
and acct_id
and order_amt
and order_resp_cd
create_time desc limit ?
4.使用原生sql查询出Map集合
使用原生sql进行表关联查询,返回值一般都用List&Object[]&来接收,这种方法很不利于项目的维护,你并不一定记得Object[0]是什么字段,一旦sql发生变化,则整个Object[]数组的顺序就会发生变化.
public List&Object[]& findById(int id) {
String sql = "select u.*,c.* from user u,commont c where u.id = c.id and id=?1";
Query query = entityManager.createNativeQuery(sql);
query.setParameter(1,id);
return query.getResultList();
那么就要改进,使其返回Map
public List findById (int id) {
String sql = "select u.*,c.* from user u,commont c where u.id = c.id and id=?1";
Query query = entityManager.createNativeQuery(sql);
query.setParameter(1,id);
//转换为Map集合
query.unwrap(org.hibernate.SQLQuery.class).setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);
return query.getResultList();
//实际上返回的是一个List&Map&集合
这样的返回值是一个List&Map&类型,取出的时候直接根据键值取即可.
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