<Spring Boot / Hibernate> 调用 Jpa Repository.findAll 时的调用异常（示例）答案

【问题标题】：<SpringBoot / Hibernate> InvocationException on calling JpaRepository.findAll(Example example)<Spring Boot / Hibernate> 调用 Jpa Repository.findAll 时的调用异常（示例）
【发布时间】：2021-03-02 17:51:34
【问题描述】：

我注意到在 H2 数据库上执行 JpaRepository.findAll(Example example) 时返回了 InvocationException。

当我尝试配置“Account”和“Transaction”这两个表之间的外键关系时会出现这种情况（即一个帐户可以有许多交易，但一个交易只能属于一个帐户）。

在我添加 @OneToMany 和 @ManyToOne 注释之前，没有任何问题。

欢迎任何帮助，谢谢。

请求：

查询成功，但它给出了一个 InvocationException，这反过来又给出了一个 HTTP500。

服务：

AccountService.java

...
......
public List<Transaction> getAllTransactions(Account account) {

    TransactionPK inputTransactionPK = new TransactionPK();
    inputTransactionPK.setAccountNum(account.getAccountNum());

    Transaction inputTransaction = new Transaction();
    inputTransaction.setTransactionPK(inputTransactionPK);

    ExampleMatcher matcher = ExampleMatcher.matchingAll().withIgnorePaths("debitAmt", "creditAmt");

    Example<Transaction> example = Example.of(inputTransaction, matcher);

    List<Transaction> transactionList = transactionRepository.findAll(example);

    log.info("##################################################\n"
            + "Retrieved transaction list for account with account number " + account.getAccountNum()
            + "\n##################################################");

    return transactionList;
}
...
......

表模型：

Account.java

package com.somecompany.account.model;

import java.sql.Timestamp;
import java.util.Set;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.validation.constraints.DecimalMin;
import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.Pattern;
import javax.validation.constraints.Size;

import lombok.Data;

@Entity
@Data
public class Account {

    @OneToMany(mappedBy = "account")
    private Set<Transaction> transaction;

    @Column(name = "cust_id")
    @NotEmpty(message = "Customer ID cannot be null nor empty")
    @Pattern(regexp = "^[0-9]+$", message = "Customer ID must be a number")
    @Min(value = 1L, message = "Customer ID must not be less than 1")
    @Max(value = 9999999999L, message = "Customer ID must not be larger than 9999999999")
    private long custId;

    @Column(name = "account_num")
    @Id
    @NotEmpty(message = "Account number cannot be null nor empty")
    @Pattern(regexp = "^[0-9]+$", message = "Account number must be a number")
    @Min(value = 1L, message = "Account number  must not be less than 1")
    @Max(value = 9999999999L, message = "Account number must not be larger than 9999999999")
    private long accountNum;

    @Column(name = "account_name")
    @NotEmpty(message = "Account name cannot be null nor empty")
    @Size(min = 1, max = 30, message = "Account name must have length between 1 and 30")
    private String accountName;

    @Column(name = "account_type")
    @NotEmpty(message = "Account type cannot be null nor empty")
    @Size(min = 1, max = 7, message = "Account type must have length between 1 and 7")
    private String accountType;

    @Column(name = "balance_date")
    @NotEmpty(message = "Balance date cannot be null nor empty")
    private Timestamp balanceDate;

    @Column(name = "currency")
    @NotEmpty(message = "Currency cannot be null nor empty")
    @Size(min = 3, max = 3, message = "Currency must have length exactly equal to 3")
    private String currency;

    @Column(name = "opening_available_balance", columnDefinition = "Decimal(20,2) default '0.0'")
    @NotEmpty(message = "Opening available balance cannot be null nor empty")
    @Pattern(regexp = "^[0-9.]+$", message = "Opening available balance must be a decimal number")
    @DecimalMin(value = "0.0", message = "Opening available balance cannot be negative")
    private float openingAvailableBalance;
}

Transaction.java

package com.somecompany.account.model;

import javax.persistence.Column;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.validation.constraints.DecimalMin;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.Size;

import lombok.Data;

@Entity
@Data
public class Transaction {

    @ManyToOne
    @JoinColumn(name = "account_num", referencedColumnName = "account_num", insertable = false, updatable = false, nullable = false)
    private Account account;

    @EmbeddedId
    private TransactionPK transactionPK;

    @Column(name = "account_name")
    @NotEmpty(message = "Account name cannot be null nor empty")
    @Size(min = 1, max = 30, message = "Account name must have length between 1 and 30")
    private String accountName;

    @Column(name = "currency")
    @NotEmpty(message = "Currency cannot be null nor empty")
    @Size(min = 3, max = 3, message = "Currency must have length exactly equal to 3")
    private String currency;

    @Column(name = "debit_amt", columnDefinition = "Decimal(20,2) default '0.0'")
    @NotEmpty(message = "Debit amount cannot be null nor empty")
    @DecimalMin(value = "0.0", message = "Debit amount cannot be negative")
    private float debitAmt;

    @Column(name = "credit_amt", columnDefinition = "Decimal(20,2) default '0.0'")
    @NotEmpty(message = "Credit amount cannot be null nor empty")
    @DecimalMin(value = "0.0", message = "Credit amount cannot be negative")
    private float creditAmt;

    @Column(name = "debit_credit")
    @NotEmpty(message = "Debit/Credit cannot be null nor empty")
    @Size(min = 1, max = 6, message = "Debit/Credit must have length between 1 and 6")
    private String debitCredit;

    @Column(name = "transaction_narrative")
    @Size(min = 0, max = 50, message = "Transaction narrative must have length between 0 and 50")
    private String transactionNarrative;
}

TransactionPK.java

package com.somecompany.account.model;

import java.io.Serializable;
import java.sql.Timestamp;

import javax.persistence.Column;
import javax.persistence.Embeddable;
import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.Pattern;

import lombok.Data;

@Embeddable
@Data
public class TransactionPK implements Serializable {

    /**
    * 
    */
    private static final long serialVersionUID = 1L;

    @Column(name = "account_num")
    @NotEmpty(message = "Account number cannot be null nor empty")
    @Pattern(regexp = "^[0-9]+$", message = "Account number must be a number")
    @Min(value = 1L, message = "Account number  must not be less than 1")
    @Max(value = 9999999999L, message = "Account number must not be larger than 9999999999")
    private long accountNum;

    @Column(name = "value_date")
    @NotEmpty(message = "Value date cannot be null nor empty")
    private Timestamp valueDate;
}

H2 DB 主键和外键信息：

SpringBoot 应用启动时的示例数据库数据（data.sql）：

INSERT INTO ACCOUNT (cust_id, account_num, account_name, account_type, balance_date, currency, opening_available_balance) VALUES
(1111111111, 1111111111, 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA', 'Savings', TIMESTAMP '2020-11-01 11:01:01', 'SGD', 99999.99),
(2, 2, 'B', 'Savings', TIMESTAMP '2020-11-02 11:02:02', 'AUD', 0.0),
(1111111111, 3333333333, 'CCCCCCCCCCCCCCCCCCCCCCCCCCCCCC', 'Current', TIMESTAMP '2020-11-03 11:03:03', 'USD', 99999.99);

INSERT INTO TRANSACTION (account_num, account_name, value_date, currency, debit_amt, credit_amt, debit_credit, transaction_narrative) VALUES
(1111111111, 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA', TIMESTAMP '2012-11-01 11:01:01', 'SGD', 0.0, 99999.99, 'Credit', 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'),
(2, 'Savings Account', TIMESTAMP '2012-11-02 11:02:02', 'USD', 0.1, 0.0, 'Debit', null),
(1111111111, 'CCCCCCCCCCCCCCCCCCCCCCCCCCCCCC', TIMESTAMP '2012-11-03 11:03:03', 'USD', 99999.99, 0.0, 'Debit', 'CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC');

【问题讨论】：

标签： java spring-boot hibernate jpa h2

【解决方案1】：

经过一番调查，我做了以下更改，应用程序最终按预期运行。

帐户.java

import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.List;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.validation.constraints.DecimalMin;
import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.Pattern;
import javax.validation.constraints.Size;

import com.fasterxml.jackson.annotation.JsonBackReference;

import lombok.Getter;
import lombok.Setter;

@Entity
@Getter
@Setter
/**
* The model class for "Account" table.
* 
* @author patrick
*
*/
public class Account {

    @OneToMany(mappedBy = "transactionPK.account")
    @JsonBackReference
    private List<Transaction> transactions = new ArrayList<>();

    @Column(name = "cust_id")
    @NotEmpty(message = "Customer ID cannot be null nor empty")
    @Pattern(regexp = "^[0-9]+$", message = "Customer ID must be a number")
    @Min(value = 1L, message = "Customer ID must not be less than 1")
    @Max(value = 9999999999L, message = "Customer ID must not be larger than 9999999999")
    private long custId;

    @Column(name = "account_num")
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @NotEmpty(message = "Account number cannot be null nor empty")
    @Pattern(regexp = "^[0-9]+$", message = "Account number must be a number")
    @Min(value = 1L, message = "Account number  must not be less than 1")
    @Max(value = 9999999999L, message = "Account number must not be larger than 9999999999")
    private long accountNum;

    @Column(name = "account_name")
    @NotEmpty(message = "Account name cannot be null nor empty")
    @Size(min = 1, max = 30, message = "Account name must have length between 1 and 30")
    private String accountName;

    @Column(name = "account_type")
    @NotEmpty(message = "Account type cannot be null nor empty")
    @Size(min = 1, max = 7, message = "Account type must have length between 1 and 7")
    private String accountType;

    @Column(name = "balance_date")
    @NotEmpty(message = "Balance date cannot be null nor empty")
    private Timestamp balanceDate;

    @Column(name = "currency")
    @NotEmpty(message = "Currency cannot be null nor empty")
    @Size(min = 3, max = 3, message = "Currency must have length exactly equal to 3")
    private String currency;

    @Column(name = "opening_available_balance", columnDefinition = "Decimal(20,2) default '0.0'")
    @NotEmpty(message = "Opening available balance cannot be null nor empty")
    @Pattern(regexp = "^[0-9.]+$", message = "Opening available balance must be a decimal number")
    @DecimalMin(value = "0.0", message = "Opening available balance cannot be negative")
    private float openingAvailableBalance;
}

Transaction.java

import javax.persistence.Column;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.validation.constraints.DecimalMin;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.Size;

import lombok.Getter;
import lombok.Setter;

@Entity
@Getter
@Setter
/**
* The model class for "Transaction" table.
* 
* @author patrick
*
*/
public class Transaction {

    @EmbeddedId
    private TransactionPK transactionPK;

    @Column(name = "account_name")
    @NotEmpty(message = "Account name cannot be null nor empty")
    @Size(min = 1, max = 30, message = "Account name must have length between 1 and 30")
    private String accountName;

    @Column(name = "currency")
    @NotEmpty(message = "Currency cannot be null nor empty")
    @Size(min = 3, max = 3, message = "Currency must have length exactly equal to 3")
    private String currency;

    @Column(name = "debit_amt", columnDefinition = "Decimal(20,2) default '0.0'")
    @NotEmpty(message = "Debit amount cannot be null nor empty")
    @DecimalMin(value = "0.0", message = "Debit amount cannot be negative")
    private float debitAmt;

    @Column(name = "credit_amt", columnDefinition = "Decimal(20,2) default '0.0'")
    @NotEmpty(message = "Credit amount cannot be null nor empty")
    @DecimalMin(value = "0.0", message = "Credit amount cannot be negative")
    private float creditAmt;

    @Column(name = "debit_credit")
    @NotEmpty(message = "Debit/Credit cannot be null nor empty")
    @Size(min = 1, max = 6, message = "Debit/Credit must have length between 1 and 6")
    private String debitCredit;

    @Column(name = "transaction_narrative")
    @Size(min = 0, max = 50, message = "Transaction narrative must have length between 0 and 50")
    private String transactionNarrative;
}

TransactionPK.java

import java.io.Serializable;
import java.sql.Timestamp;

import javax.persistence.Column;
import javax.persistence.Embeddable;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.validation.constraints.NotEmpty;

import com.fasterxml.jackson.annotation.JsonManagedReference;

import lombok.Data;

@Embeddable
@Data
/**
* The model class for the EmbeddedId (i.e. primary key) of the "Transaction" table.
* 
* @author patrick
*
*/
public class TransactionPK implements Serializable {

    /**
    * 
    */
    private static final long serialVersionUID = 1L;

    @ManyToOne
    @JoinColumn(name = "account_num", referencedColumnName = "account_num", insertable = false, updatable = false, nullable = false)
    @JsonManagedReference
    private Account account;

    @Column(name = "value_date")
    @NotEmpty(message = "Value date cannot be null nor empty")
    private Timestamp valueDate;
}

我在 TransactionPK 中创建了一个“account”字段来替换“account_num”字段（无论如何，account 对象已经具有“account_num”信息），并用 @ManyToOne 对其进行了注释。这是因为关系是“一个账户可以有很多交易（即交易列表），但一个交易只属于一个账户”。关系是对象级别的，而不是字段级别的。

对于“Account”中的“List transactions”和“TransactionPK”中的“Account account”，它们仅用于指示外键关系，它们不必存在于JSON文件中。如果我们就这样放着不管，在序列化为 JSON 时会出现无限递归错误（因为每个元素都有另一个元素，所以它永远无法完成 JSON 的生成）。

为了解决这个问题，我们可以用@JsonIgnore 标记这些字段，这将跳过序列化这两个字段。或者如果我们需要显示一个而不显示另一个（例如在 Transaction JSON 中显示“帐户”，但在 Account JSON 中不显示“交易”），那么我们可以使用@JsonManagedReference 注释我们想要保留的一个，并标记我们不想用 @JsonBackReference 在 JSON 中显示的那个。

参考： https://www.baeldung.com/jackson-bidirectional-relationships-and-infinite-recursion

我做的另一个改变是没有使用@Data。避免在处理实体时使用来自 lombok 的 @Data，如果它们将与 JPA 等 ORM 一起使用。@Data 的 equals() 和 hashCode() 实现可能会混淆对象比较。

参考： https://thorben-janssen.com/lombok-hibernate-how-to-avoid-common-pitfalls/

【讨论】：