Spring Boot -实体到json -递归

Question

我有彼此双向映射的实体。调用 REST Http.GET 请求从数据库获取所有记录，由于无限递归，我收到堆栈溢出异常。我试图使用@JsonIgnore，@JsonBackReference@JsonManageReference和@JsonIdentityInfo一起使用不同的组合，但没有积极的结果。我仍然收到错误。

SpringBoot在2.6.6版本中为我加载了jackson。

以下是我的BaseEntity：

@MappedSuperclass
public class BaseEntity {
    @Id
    @GeneratedValue
    private Long id;
    private String createdBy;
    private Date createdOn;
    private String modifiedBy;
    private Date modifiedOn;
    public String description;

    public BaseEntity() {
    }

    public Long getId() {
        return id;
    }

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

    public String getCreatedBy() {
        return createdBy;
    }

    public void setCreatedBy(String createdBy) {
        this.createdBy = createdBy;
    }

    public Date getCreatedOn() {
        return createdOn;
    }

    public void setCreatedOn(Date createdOn) {
        this.createdOn = createdOn;
    }

    public String getModifiedBy() {
        return modifiedBy;
    }

    public void setModifiedBy(String modifiedBy) {
        this.modifiedBy = modifiedBy;
    }

    public Date getModifiedOn() {
        return modifiedOn;
    }

    public void setModifiedOn(Date modifiedOn) {
        this.modifiedOn = modifiedOn;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
}

第一个实体类:

@Entity
public class Entry extends BaseEntity{

    private Date businessOperationDate;

    @ManyToOne
    private Version version;

    @ManyToOne
    private Status status;

    @ManyToOne
    @JsonManagedReference
    private Account account;

    public Entry() {
    }

    public Date getBusinessOperationDate() {
        return businessOperationDate;
    }

    public void setBusinessOperationDate(Date businessOperationDate) {
        this.businessOperationDate = businessOperationDate;
    }

    public Version getVersion() {
        return version;
    }

    public void setVersion(Version version) {
        this.version = version;
    }

    public Status getStatus() {
        return status;
    }

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

    public Account getAccount() {
        return account;
    }

    public void setAccount(Account account) {
        this.account = account;
    }
}

第二个：

@Entity
public class Account extends BaseEntity{
    private String number;

    @OneToMany(mappedBy = "account", fetch = FetchType.EAGER)
    @JsonBackReference
    private List<Entry> entries;

    @ManyToMany(mappedBy = "accounts")
    private List<Project> projects;

    public Account() {
    }

    public String getNumber() {
        return number;
    }

    public void setNumber(String number) {
        this.number = number;
    }

    public List<Entry> getEntries() {
        return entries;
    }

    public void setEntries(List<Entry> entries) {
        this.entries = entries;
    }

    public List<Project> getProjects() {
        return projects;
    }

    public void setProjects(List<Project> projects) {
        this.projects = projects;
    }
}

在这里，您可以找到从Http收到的部分结果。GET请求：

[{"id":1,"createdBy":null,"createdOn":null,"modifiedBy":null,"modifiedOn":null,"description":"pierwszy zapis","businessOperationDate":null,"version":null,"status":null,"account":{"id":1,"createdBy":null,"createdOn":null,"modifiedBy":null,"modifiedOn":null,"description":"pierwszy projekt","number":null,"entries":
[{"id":1,"createdBy":null,"createdOn":null,"modifiedBy":null,"modifiedOn":null,"description":"pierwszy zapis","businessOperationDate":null,"version":null,"status":null,"account":{"id":1,"createdBy":null,"createdOn":null,"modifiedBy":null,"modifiedOn":null,"description":"pierwszy projekt","number":null,"entries":
[{"id":1,"createdBy":null,"createdOn":null,"modifiedBy":null,"modifiedOn":null,"description":"pierwszy zapis","{"timestamp":1468778765328,"status":200,"error":"OK","exception":"org.springframework.http.converter.HttpMessageNotWritableException","message":
"Could not write content: Infinite recursion (StackOverflowError) (through reference chain: com.test.test2.core.dto.AccountDto[\"entries\"]->
java.util.ArrayList[0]->com.test.test2.core.dto.EntryDto[\"account\"]->com.test.test2.core.dto.AccountDto[\"entries\"]->
java.util.ArrayList[0]->com.test.test2.core.dto.EntryDto[\"account\"]->com.test.test2.core.dto.AccountDto[\"entries\"]->java.util.ArrayList[0]->com.test.test2.core.dto.EntryDto[\"account\"]->com.test.test2.core.dto.AccountDto[\"entries\"]->
java.util.ArrayList[0]->com.test.test2.core.dto.EntryDto[\"account\"]-

pom公司。xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://html" target="_blank">maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.test</groupId>
    <artifactId>test2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>test2</name>
    <description>test2</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <!--<dependency>-->
            <!--<groupId>org.springframework.boot</groupId>-->
            <!--<artifactId>spring-boot-starter-security</artifactId>-->
        <!--</dependency>-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
            <version>9.4-1201-jdbc41</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!-- model mapper -->
        <dependency>
            <groupId>ma.glasnost.orika</groupId>
            <artifactId>orika-core</artifactId>
            <version>1.4.6</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

请告诉我，我做错了什么。我希望在结果中只收到一个级别，例如调用getAll（）作为条目，我希望收到所有条目，其中包含与哪个帐户相关的信息，相反，一旦调用getAll（）作为帐户。

Answer 1

我搜索更多次这个错误，但我可以满足任何我得到这个错误的情况，我通过在一些关系映射中添加注释@JsonIgnore来纠正它，

这是一个例子

  @ManyToMany(mappedBy = "accounts")
    @JsonIgnore
    private List<Project> projects;