Question

我使用技术jpa，休眠，春季启动-数据，api REST。

我遇到以下错误：

org.springframework.beans.factory.UnsatisfiedDependencyException：创建名称为“ walletRestService”的bean时出错：通过字段“ walletRepository”表示的不满足的依赖关系；嵌套的异常是org.springframework.beans.factory.BeanCreationException：创建名称为'walletRepository'的bean时出错：调用init方法失败；嵌套异常是java.lang.IllegalArgumentException：无法创建查询方法公共抽象java.lang.Long com.wj.dao.WalletRepository.createWallet（java.lang.Long，java.lang.String）！找不到电子钱包类型的属性createWallet！

这是我的代码：

实体用户：

package com.wj.entities;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;

import com.fasterxml.jackson.annotation.JsonManagedReference;

@Entity
public class User implements Serializable{

@Id
@GeneratedValue
private Long id; 
private String name;

@OneToMany(mappedBy="user", fetch=FetchType.LAZY)
@JsonManagedReference
private List<Wallet> wallets = new ArrayList<>();

public User() {
    super();
}

public User(String name) {
    super();
    this.name = name;
}



public User(Long id, String name) {
    super();
    this.id = id;
    this.name = name;
}



public User(Long id, String name, List<Wallet> wallets) {
    super();
    this.id = id;
    this.name = name;
    this.wallets = wallets;
}

public Long getId() {
    return id;
}

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

public String getName() {
    return name;
}

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

public List<Wallet> getWallets() {
    return wallets;
}

public void setWallets(List<Wallet> wallets) {
    this.wallets = wallets;
}


}

实体钱包：

@Id
@GeneratedValue
private Long id;
private String name;
@ManyToOne
@JoinColumn(name="user_id")
@JsonBackReference    
private User user;

public Wallet() {
    super();
}




public Wallet(String name, User user) {
    super();
    this.name = name;
    this.user = user;
}




public Wallet(Long id, String name, User user) {
    super();
    this.id = id;
    this.name = name;
    this.user = user;
}



public Long getId() {
    return id;
}

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

public String getName() {
    return name;
}

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

public User getUser() {
    return user;
}

public void setUser(User user) {
    this.user = user;
}


}

restApi：

@RequestMapping(value="/wallets", method=RequestMethod.POST)
public Wallet save(@RequestBody Wallet wallet) {
    User user = wallet.getUser();

    Long id = walletRepository.createWallet(user.getId(), wallet.getName());
    User boundUser = wallet.getUser();
    User simpleUser = new User(boundUser.getId(), boundUser.getName());
    wallet = new Wallet(id, wallet.getName(), simpleUser);
    return walletRepository.save(wallet);
}

DAO:  

package com.wj.dao;
import org.springframework.data.jpa.repository.JpaRepository;
import com.wj.entities.Wallet;

public interface WalletRepository extends JpaRepository<Wallet, Long>{
   Long createWallet(Long id, String name);
}

Answer 1

WalletRepository界面中的此声明对Spring无效：

Long createWallet(Long id, String name);

您希望Spring怎样猜测createWallet()方法是用来创建并持久保存带有Wallet和Long id的{{1}}实体的？

实际上，您在String name接口中声明的方法是依赖命名约定的检索方法，以允许Spring为您创建查询。并且WalletRepository在Spring Data文档中没有被引用：

4.4.2. Query Creation

该机制会删除前缀create，find…By，read…By，   query…By和count…By中的方法，然后开始解析   它。

由于Spring无法识别get…By，因此它可能尝试将create解析为实体的字段。消息：

找不到类型为电子钱包的属性createWallet！

要保存实体，请改用createWallet中提供的方法：

JpaRepository

您的存储库的哪个将推断为：

<S extends T> S save(S entity);

并修改客户端代码以创建Wallet save(Wallet entity);实例并将其传递给Wallet。

例如：

save()

Answer 2

尝试按照您的指示做，他向我显示以下错误：

org.springframework.beans.factory.BeanCreationException：创建在类路径资源[org / springframework / boot / autoconfigure / orm / jpa / HibernateJpaAutoConfiguration.class]中定义的名称为'entityManagerFactory'的bean时出错：调用init方法失败；嵌套的异常是org.hibernate.AnnotationException：集合没有定义泛型或OneToMany.targetEntity（）：com.wj.entities.User.wallets

WalletRepository：DAO

public interface WalletRepository extends JpaRepository<Wallet, Long>{

Long save(Long id, String name);

 }

RestService：

@RequestMapping(value="/wallets", 
method=RequestMethod.POST)
public Wallet save(@RequestBody Wallet wallet) {
    User user = wallet.getUser();

    Long id = walletRepository.save(user.getId(), wallet.getName());
    User boundUser = wallet.getUser();
    User simpleUser = new User(boundUser.getId(), boundUser.getName());
    wallet = new Wallet(id, wallet.getName(), simpleUser);
    return walletRepository.save(wallet);
}

实体：用户我修改了：

@OneToMany(mappedBy="user", fetch=FetchType.LAZY)
@JsonManagedReference
private List<? extends Wallet> wallets = new ArrayList<>();

java.lang.IllegalArgumentException：无法在JpaRepository中创建查询方法

2 个答案: