Spingboot JPA CriteriaBuilder 如何获取指定字段

Spingboot JPA CriteriaBuilder获取指定字段

废话不说直接贴代码

public class ActivityVO implements Serializable {
private static final long serialVersionUID = 1L;  
private int id;
private String name;
private String thumb;
public ActivityVO(int id, String name, String thumb) {
 this.id    = id;
 this.name  = name;
 this.thumb = thumb;
}

public ActivityVO(){
}

public int getId() {
 return id;
}

public void setId(int id) {
 this.id = id;
}

public String getName() {
 return name;
}

public void setName(String name) {
 this.name = name;
}

public String getThumb() {
 return thumb;
}

public void setThumb(String thumb) {
 this.thumb = thumb;
}  
}

import org.hibernate.annotations.NotFound;
import org.hibernate.annotations.NotFoundAction;
import java.io.Serializable;
import javax.persistence.*;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.List;
import java.util.Map;
import java.util.Objects;

/**
* The persistent class for the activity database table.
*
*/
@Entity
@Table(name="activity")
//@JsonIgnoreProperties({"user"})
//@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
//@NamedQuery(name = "Task.findByTaskName", query = "select t from Task t where t.taskName = ?1")
public class ActivityEntity implements Serializable {
private static final long serialVersionUID = 1L;
public ActivityEntity(int id, String name, String thumb) {
this.id                  = id;
this.name                = name;
}

private int        id;
private Integer    userId;
private String     name;
private String     thumb;
private byte       type;
private byte       mode;
private String     notes;
private String     content;
private BigDecimal deposit;
private byte       status;
private int        productNum;
private Integer    participantNum;
private Integer    wxId;
private Integer    mpId;
private String     mpRelpyKeyword;
private BigInteger startTime;
private byte       lotteryType;
private BigInteger lotteryTime;
private int        maxParticipantNum;
private byte       enableBlacklist;
   private byte enableSharing;
private byte isVisible;
private BigInteger createTime;
private BigInteger updateTime;
public ActivityEntity() {
}

@Id
@Column(name = "id")
@GeneratedValue(strategy=GenerationType.IDENTITY)
public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

@Basic
@Column(name = "user_id")
public Integer getUserId() {
return userId;
}

public void setUserId(Integer userId) {
this.userId = userId;
}

@Basic
@Column(name = "name")
public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

@Basic
@Column(name = "thumb")
public String getThumb() {
return thumb;
}

public void setThumb(String thumb) {
this.thumb = thumb;
}

@Basic
@Column(name = "type")
public byte getType() {
return type;
}

public void setType(byte type) {
this.type = type;
}

@Basic
@Column(name = "mode")
public byte getMode() {
return mode;
}

public void setMode(byte mode) {
this.mode = mode;
}

@Basic
@Column(name = "notes")
public String getNotes() {
return notes;
}

public void setNotes(String notes) {
this.notes = notes;
}

@Basic
@Column(name = "content")
public String getContent() {
return content;
}

public void setContent(String content) {
this.content = content;
}

@Basic
@Column(name = "deposit")
public BigDecimal getDeposit() {
return deposit;
}

public void setDeposit(BigDecimal deposit) {
this.deposit = deposit;
}

@Basic
@Column(name = "status")
public byte getStatus() {
return status;
}

public void setStatus(byte status) {
this.status = status;
}

@Basic
@Column(name = "product_num")
public int getProductNum() {
return productNum;
}

public void setProductNum(int productNum) {
this.productNum = productNum;
}

@Basic
@Column(name = "participant_num")
public Integer getParticipantNum() {
return participantNum;
}

public void setParticipantNum(Integer participantNum) {
this.participantNum = participantNum;
}

@Basic
@Column(name = "wx_id")
public Integer getWxId() {
return wxId;
}

public void setWxId(Integer wxId) {
this.wxId = wxId;
}

@Basic
@Column(name = "mp_id")
public Integer getMpId() {
return mpId;
}

public void setMpId(Integer mpId) {
this.mpId = mpId;
}

@Basic
@Column(name = "mp_relpy_keyword")
public String getMpRelpyKeyword() {
return mpRelpyKeyword;
}

public void setMpRelpyKeyword(String mpRelpyKeyword) {
this.mpRelpyKeyword = mpRelpyKeyword;
}

@Basic
@Column(name = "start_time")
public BigInteger getStartTime() {
return startTime;
}
public void setStartTime(BigInteger startTime) {
this.startTime = startTime;
}

@Basic
@Column(name = "lottery_type")
public byte getLotteryType() {
return lotteryType;
}

public void setLotteryType(byte lotteryType) {
this.lotteryType = lotteryType;
}

@Basic
@Column(name = "lottery_time")
public BigInteger getLotteryTime() {
return lotteryTime;
}

public void setLotteryTime(BigInteger lotteryTime) {
this.lotteryTime = lotteryTime;
}

@Basic
@Column(name = "max_participant_num")
public int getMaxParticipantNum() {
return maxParticipantNum;
}

public void setMaxParticipantNum(int maxParticipantNum) {
this.maxParticipantNum = maxParticipantNum;
}

@Basic
@Column(name = "enable_blacklist")
public byte getEnableBlacklist() {
return enableBlacklist;
}

public void setEnableBlacklist(byte enableBlacklist) {
this.enableBlacklist = enableBlacklist;
}

@Basic
@Column(name = "enable_sharing")
public byte getEnableSharing() {
return enableSharing;
}

public void setEnableSharing(byte enableSharing) {
this.enableSharing = enableSharing;
}

@Basic
@Column(name = "is_visible")
public byte getIsVisible() {
return isVisible;
}

public void setIsVisible(byte isVisible) {
this.isVisible = isVisible;
}
@Basic
@Column(name = "create_time")
public BigInteger getCreateTime() {
return createTime;
}
public void setCreateTime(BigInteger createTime) {
this.createTime = createTime;
}

@Basic
@Column(name = "update_time")
public BigInteger getUpdateTime() {
return updateTime;
}

public void setUpdateTime(BigInteger updateTime) {
this.updateTime = updateTime;
}

@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
ActivityEntity that = (ActivityEntity) o;
return id == that.id &&
type == that.type &&
mode == that.mode &&
status == that.status &&
productNum == that.productNum &&
lotteryType == that.lotteryType &&
maxParticipantNum == that.maxParticipantNum &&
enableBlacklist == that.enableBlacklist &&
Objects.equals(userId, that.userId) &&
Objects.equals(name, that.name) &&
Objects.equals(thumb, that.thumb) &&
Objects.equals(notes, that.notes) &&
Objects.equals(content, that.content) &&
Objects.equals(deposit, that.deposit) &&
Objects.equals(participantNum, that.participantNum) &&
Objects.equals(wxId, that.wxId) &&
Objects.equals(mpId, that.mpId) &&
Objects.equals(mpRelpyKeyword, that.mpRelpyKeyword) &&
Objects.equals(startTime, that.startTime) &&
Objects.equals(lotteryTime, that.lotteryTime) &&
Objects.equals(createTime, that.createTime) &&
Objects.equals(updateTime, that.updateTime) &&
Objects.equals(user, that.user);
}

@Override
public int hashCode() {
return Objects.hash(id, userId, name, thumb, type, mode, notes, content, deposit, status, productNum, participantNum, wxId, mpId, mpRelpyKeyword, startTime, lotteryType, lotteryTime, maxParticipantNum, enableBlacklist, createTime, updateTime, user);
}

@Override
public String toString() {
return "ActivityEntity{" +
"id=" + id +
", userId=" + userId +
", name='" + name + '\'' +
", thumb='" + thumb + '\'' +
", type=" + type +
", mode=" + mode +
", notes='" + notes + '\'' +
", content='" + content + '\'' +
", deposit=" + deposit +
", status=" + status +
", productNum=" + productNum +
", participantNum=" + participantNum +
", wxId=" + wxId +
", mpId=" + mpId +
", mpRelpyKeyword='" + mpRelpyKeyword + '\'' +
", startTime=" + startTime +
", lotteryType=" + lotteryType +
", lotteryTime=" + lotteryTime +
", maxParticipantNum=" + maxParticipantNum +
", enableBlacklist=" + enableBlacklist +
", createTime=" + createTime +
", updateTime=" + updateTime +
", user=" + user +
'}';
}
}

@PersistenceContext//@Autowired和@PersistenceContext注解任取一
   EntityManager entityManager;
   public List<ActivityVO> findAllByPage(Pageable pageable) throws Exception {
       CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
       CriteriaQuery<Tuple> criteriaQuery = criteriaBuilder.createTupleQuery();
       Root<ActivityEntity> root = criteriaQuery.from(ActivityEntity.class);
       criteriaQuery.multiselect( root.get("id"), root.get("name"),root.get("thumb") );

Predicate restrictions = criteriaBuilder.conjunction();
       restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.equal(root.get("id"), 1));
       criteriaQuery.where(restrictions);
       criteriaQuery.orderBy(criteriaBuilder.desc(root.get("id")));

TypedQuery<Tuple> query = entityManager.createQuery(criteriaQuery).setFlushMode(FlushModeType.COMMIT);
       List<Tuple> tuples = query.getResultList();

ActivityVO adminWrapper = null;
       List<ActivityVO> lists = new ArrayList<ActivityVO>();
       for (Tuple t : tuples) {
           adminWrapper = new ActivityVO();
           adminWrapper.setId((Integer) t.get(0));
           adminWrapper.setName((String)t.get(1));
           adminWrapper.setThumb((String)t.get(2));
           lists.add(adminWrapper);
       }
       return lists;  
   }  
}

Java JPA CriteriaBuilder使用

一个复杂的查询例子

包含常用的所有查询方法

CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder(); //查询结果所需要的类型(Entity相对应)
       CriteriaQuery<Entity> criteriaQuery = criteriaBuilder.createQuery(Entity.class); //查询所需要的主体类（Entity0相对应）
       Root<Entity0> root = criteriaQuery.from(Entity0.class); //查询结果-select（此处查询所有符合条件的主体类）
       criteriaQuery.select(root); //过滤条件用Predicate方法拼接
       Predicate restrictions = criteriaBuilder.conjunction(); //过滤条件——equal（当Entity0关联member类时，Entity0：member=m：1）
       restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.equal(root.get("member"), member));
       //过滤条件——like
       restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.like(root.<String>get("str"), "％"+str+"％"));
       //用户名查询（member里面的username匹配） ———— 多层查询 ———— 子查询的一种：适用于m:1或1:1（即多对一或一对一）
       restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.like(root.get("member").<String>get("username"), "％"+username+"％"));
       //子查询（规范写法，先判断查询内容是否存在）（适用于1：m）（即一对多）
       if (searchType != null || searchValue != null || hasExpired != null || status != null || type != null || isPendingReceive != null || isPendingRefunds != null || isAllocatedStock != null || businessType != null) {
           //建立子查询  Subquery<Order> orderSubquery = criteriaQuery.subquery(Order.class);
           Root<Order> orderSubqueryRoot = orderSubquery.from(Order.class);
           orderSubquery.select(orderSubqueryRoot);//子查询和父查询相关联
           Predicate orderRestrictions = criteriaBuilder.equal(orderSubqueryRoot.<MergeOrder>get("mergeOrder"), root);
           //子查询过滤条件拼接
           if (searchType != null && searchValue != null) {if ("phone".equals(searchType)) {
                   orderRestrictions = criteriaBuilder.and(orderRestrictions, criteriaBuilder.like(orderSubqueryRoot.<String>get("phone"), "％"+searchValue+"％"));
               }
           }if (type != null) {
               CriteriaBuilder.In<Order.Type> in = criteriaBuilder.in(orderSubqueryRoot.<Order.Type>get("type"));
               in.value(type);
               orderRestrictions = criteriaBuilder.and(orderRestrictions, in);
           }
           //and、or以及判断是否为null，比较（>）的使用（比较可以用于日期比较）
           if (hasExpired != null) {
               orderRestrictions = criteriaBuilder.and(orderRestrictions, criteriaBuilder.or(orderSubqueryRoot.get("expire").isNull(), criteriaBuilder.greaterThan(orderSubqueryRoot.<Date>get("expire"), new Date())));
           }
           // not的使用方法（不符合上述过滤条件），notEqual的使用，<（小于）的使用
           if (isPendingReceive != null) {
               restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.equal(root.get("paymentMethodType"), PaymentMethod.Type.cashOnDelivery));
               Predicate predicate = criteriaBuilder.and(criteriaBuilder.or(orderSubqueryRoot.get("expire").isNull()
                       , criteriaBuilder.greaterThan(orderSubqueryRoot.<Date>get("expire"), new Date()))
                       , criteriaBuilder.notEqual(orderSubqueryRoot.get("status"), Order.Status.completed)
                       , criteriaBuilder.lessThan(orderSubqueryRoot.<BigDecimal>get("amountPaid"), orderSubqueryRoot.<BigDecimal>get("amount")));
               if (isPendingReceive) {
                   orderRestrictions = criteriaBuilder.and(orderRestrictions, criteriaBuilder.not(predicate));
               }
           }// 多层查询使用if (businessType != null) {
               orderRestrictions = criteriaBuilder.and(orderRestrictions, criteriaBuilder.equal(orderSubqueryRoot.get("store").get("business").get("businessType"), businessType));
           }// 拼接过滤条件
           orderSubquery.where(orderRestrictions);
           // 和总条件拼接（exists的使用）
           restrictions = criteriaBuilder.and(restrictions, criteriaBuilder.exists(orderSubquery));
       }
       criteriaQuery.where(restrictions); TypedQuery<Entity> query = entityManager.createQuery(criteriaQuery); Entity singleResult = query.getSingleResult();

来源：https://blog.csdn.net/wjy9772/article/details/102827897