springdatajpa多表查询死循环

近期在看springdatajpa多表查询的时候，运用注解@ManyToOne()，@ManyToMany的时候，出现死循环，

老是报错Detail formatter error: An exception occurred: java.lang.StackOverflowError

自己死磕了两天才发现问题的解决方法，所以记录下 防止后面再次入坑。

前期有排查spring 前端解析json是不是有问题，使用Specification的方法是否有问题，

以ManyToOne为例，需要在字段上添加@JsonIgnore注解

@Entity
@Table(name = "tbl_dep")
public class DepModel implements Serializable {

	private static final long serialVersionUID = -1215166740441717912L;
	@Id
	private Integer uuid;
	
	private String name;
	
	//表示在tbl_dep里面有user_id的字段
	@JsonIgnore
	@ManyToOne()
	@JoinColumn(name = "user_id", nullable = false)
	private UserModel um = new UserModel();
	public Integer getUuid() {
		return uuid;
	}
	public void setUuid(Integer uuid) {
		this.uuid = uuid;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public UserModel getUm() {
		return um;
	}
	public void setUm(UserModel um) {
		this.um = um;
	}
	@Override
	public String toString() {
		return "DepModel [uuid=" + uuid + ", name=" + name + ", um=" + um + "]";
	}
}
           

@Entity
@Table(name = "tbl_dep")
public class DepModel implements Serializable {


private static final long serialVersionUID = -1215166740441717912L;
@Id
private Integer uuid;

private String name;

//表示在tbl_dep里面有user_id的字段
@JsonIgnore
@ManyToOne()
@JoinColumn(name = "user_id", nullable = false)
private UserModel um = new UserModel();
public Integer getUuid() {
return uuid;
}
public void setUuid(Integer uuid) {
this.uuid = uuid;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public UserModel getUm() {
return um;
}
public void setUm(UserModel um) {
this.um = um;
}
@Override
public String toString() {
return "DepModel [uuid=" + uuid + ", name=" + name + ", um=" + um + "]";
}
}