@JsonIgnoreProperties 解决实体中引用其他实体问题

本文介绍了如何使用Jackson库中的@JsonIgnoreProperties注解来处理JSON序列化和反序列化过程中遇到的未知字段问题。通过在实体类上添加@JsonIgnoreProperties(ignoreUnknown=true),可以忽略掉JSON中类不存在的字段,避免异常。此外,@JsonIgnoreProperties还可以用于指定忽略特定字段,如`@JsonIgnoreProperties({internalIdsecretKey}

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解决办法:

json转换成的实体类加注解@JsonIgnoreProperties(ignoreUnknown = true),注意这是类级别的注解。


@JsonIgnore注解用来忽略某些字段,可以用在Field或者Getter方法上,用在Setter方法时,和Filed效果一样。这个注解只能用在POJO存在的字段要忽略的情况,不能满足现在需要的情况。

@JsonIgnoreProperties(ignoreUnknown = true),将这个注解写在类上之后,就会忽略类中不存在的字段,可以满足当前的需要。这个注解还可以指定要忽略的字段。使用方法如下:

@JsonIgnoreProperties({ "internalId", "secretKey" })
指定的字段不会被序列化和反序列化。
 

package com.kucun.data.entity; import javax.persistence.CascadeType; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.OneToOne; import javax.persistence.Table; import com.fasterxml.jackson.annotation.JsonBackReference; import com.fasterxml.jackson.annotation.JsonManagedReference; /** 板材 @author Administrator */ @Entity @Table(name=“bancai”) public class Bancai { @Id private int id; @ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY) @JoinColumn(name = “caizhi_id”) // @JsonManagedReference // 标记为“主”关联方 private Caizhi caizhi; @ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY) @JsonBackReference @JoinColumn(name = “mupi1_id”) private Mupi mupi1; @ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY) @JoinColumn(name = “mupi2_id”) @JsonBackReference private Mupi mupi2; private Double houdu; public int getId() { return id; } public void setId(int id) { this.id = id; } public Caizhi getCaizhi() { return caizhi; } public void setCaizhi(Caizhi caizhi) { this.caizhi = caizhi; } public Mupi getMupi1() { return mupi1; } public void setMupi1(Mupi mupi1) { this.mupi1 = mupi1; } public Mupi getMupi2() { return mupi2; } public void setMupi2(Mupi mupi2) { this.mupi2 = mupi2; } public Double getHoudu() { return houdu; } public void setHoudu(Double houdu) { this.houdu = houdu; } @Override public String toString() { return “{id:” + id + “, caizhi:” + caizhi + “, mupi1:” + mupi1 + “, mupi2:” + mupi2 + “, houdu:” + houdu + “}”; } public Bancai(int id, Caizhi caizhi, Mupi mupi1, Mupi mupi2, Double houdu) { super(); this.id = id; this.caizhi = caizhi; this.mupi1 = mupi1; this.mupi2 = mupi2; this.houdu = houdu; } public Bancai() { super(); } } package com.kucun.data.entity; import java.util.List; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToMany; import javax.persistence.Table; import com.fasterxml.jackson.annotation.JsonIgnoreProperties; /** 板材材质 @author Administrator */ @Entity @Table(name=“caizhi”) @JsonIgnoreProperties({“hibernateLazyInitializer”, “handler”}) public class Caizhi { @Id private int id ; private String name; @OneToMany(mappedBy=“caizhi”) private List<Bancai> bancais; 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; } @Override public String toString() { return “{id:” + id + “, name:” + name + “}”; } public Caizhi(int id, String name) { super(); this.id = id; this.name = name; } public Caizhi() { super(); } // 添加反向关联维护方法 public void addBancai(Bancai bancai) { bancais.add(bancai); bancai.setCaizhi(this); } // 添加移除方法 public void removeBancai(Bancai bancai) { bancais.remove(bancai); bancai.setCaizhi(null); } } package com.kucun.data.entity; import java.util.List; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.ManyToMany; import javax.persistence.OneToMany; import javax.persistence.Table; import com.fasterxml.jackson.annotation.JsonIgnoreProperties; /** 木皮 @author Administrator */ @Entity @Table(name=“mupi”) @JsonIgnoreProperties({“hibernateLazyInitializer”, “handler”}) public class Mupi { @Id private int id; private String name; // 添加 OneToMany 映射 @OneToMany(mappedBy = "mupi1") // 指向 Bancai 中的 mupi1 字段 private List<Bancai> bancaisForMupi1; @OneToMany(mappedBy = "mupi2") // 指向 Bancai 中的 mupi2 字段 private List<Bancai> bancaisForMupi2; public Mupi(int id, String name, List<Bancai> bancaisForMupi1, List<Bancai> bancaisForMupi2) { super(); this.id = id; this.name = name; this.bancaisForMupi1 = bancaisForMupi1; this.bancaisForMupi2 = bancaisForMupi2; } public List<Bancai> getBancaisForMupi1() { return bancaisForMupi1; } public void setBancaisForMupi1(List<Bancai> bancaisForMupi1) { this.bancaisForMupi1 = bancaisForMupi1; } public List<Bancai> getBancaisForMupi2() { return bancaisForMupi2; } public void setBancaisForMupi2(List<Bancai> bancaisForMupi2) { this.bancaisForMupi2 = bancaisForMupi2; } @Override public String toString() { return "{id:" + id + ", name:" + name + "}"; } 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 Mupi(int id, String name) { super(); this.id = id; this.name = name; } public Mupi() { super(); } } 如何在程序中决定是否连级查找并只查找一级 ,关联的集合中的实体不会再查询它内部的集合,
06-04
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