[英]How to convert JSON Object to JSON Array and map it to custom POJO?
[英]How to map array in the JSON body to a POJO?
我正在使用Hibernate作为JPA和spring-boot来实现多对多关系。 当我从POSTMAN发出发帖请求时,出现以下错误:
Failed to convert from type [java.net.URI] to type [com.domain.Datasource]
Metric
和Datasource
之间存在多对多关系。
JSON正文
{
"companyId" : "fake_company_id",
"name" : "test_name",
"description" :"test Description",
"datasources" : ["fdaea7d4162bd2c3f3db5ba059638123"]
}
Metric.java
@Entity
public class Metric implements Persistable<Long> {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(nullable = false)
@RestResource(exported = false)
private Long id;
@Column(nullable = false, unique = true)
private String publicId;
@Column(nullable = false)
private String name;
private MetricType type;
@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name = "metric_datasource", joinColumns = @JoinColumn(name = "metric_id", referencedColumnName = "id"), inverseJoinColumns = @JoinColumn(name = "datasource_id", referencedColumnName = "id"))
private Set<Datasource> datasources ;
private String definition;
private long dateCreated;
private String description;
private String companyId;
protected Metric() {
this.dateCreated = new Date().getTime();
}
public Metric(String name, String publicId, String definition) {
super();
this.name = name;
this.publicId = publicId;
this.definition = definition;
}
@JsonIgnore
@Override
public boolean isNew() {
return null == getId();
}
@PrePersist
public void generatePublicId() {
publicId = PublicIdGenerator.generate(32);
}
@Override
public Long getId() {
return id;
}
public String getPublicId() {
return publicId;
}
public void setPublicId(String publicId) {
this.publicId = publicId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDefinition() {
return definition;
}
public void setDefinition(String definition) {
this.definition = definition;
}
public void setDateCreated(long dateCreated) {
this.dateCreated = dateCreated;
}
public long getDateCreated(){
return this.dateCreated;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public Set<Datasource> getDatasources() {
if (datasources != null) {
return datasources;
} else {
return Collections.emptySet();
}
}
public void setDatasources(Set<Datasource> datasources) {
if (datasources != null) {
this.datasources = datasources;
} else {
this.datasources = Collections.emptySet();
}
}
public void setId(Long id) {
this.id = id;
}
public String getCompanyId() {
return companyId;
}
public void setCompanyId(String companyId) {
this.companyId = companyId;
}
public MetricType getType() {
return type;
}
public void setType(MetricType type) {
this.type = type;
}
public void update(Metric metric) {
if (metric.getName() != null) {
setName(metric.getName());
}
if (metric.getDescription() != null) {
setDescription(metric.getDescription());
}
if (metric.getDefinition() != null) {
setDefinition(metric.getDefinition());
}
}
Datasource.java
@Entity
public class Datasource implements Persistable<Long> {
@Column(nullable = false, unique = true)
private String publicId;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(nullable = false)
@RestResource(exported = false)
private Long id;
@ManyToMany(mappedBy = "datasources")
private Set<Metric> metrics;
public Datasource() {
this(null);
}
public Datasource(String publicId) {
this.publicId = publicId;
}
public String getPublicId() {
return publicId;
}
public void setPublicId(String publicId) {
this.publicId = publicId;
}
@Override
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
@Override
public boolean isNew() {
return null == getId();
}
public Set<Metric> getMetrics() {
return metrics;
}
public void setMetrics(Set<Metric> metrics) {
this.metrics = metrics;
}
当前,度量标准和数据源之间的关系已正确设置,即我在数据库中创建了三个表metric
, datasource
和metric_datasource
。 但是我不确定如何使用Give JSON正文保存值。 请帮忙。
首先,确保REST控制器中的方法可以使用“ application / json”,并且在其参数中具有正确的@RequestBody
批注。
其次,我认为从客户端发送全面的类域对象是不正确的。 您应该为Metric
类实现与您提供的JSON完全匹配的DTO 。 并且在这种情况下, datasources
属性应为List<String>
其中包含实际数据源的ID。
然后,您应该在自己的方法中实现将DTO转换为域对象的方法(您可以在其中获取DTO中存储的每个数据源ID的DataSource
对象)以将其持久化。
// assuming that you already implemented any JpaRepository<Metric> interface
@Autowired
private MetricRepository metricRepo;
@Autowired
private DataSourceRepository dataSourceRepo;
public Metric saveMetricDTO(MetricDTO dto) {
Metric metric = metricRepo.findByName(dto.getName()); // or fetch by any other suitable property
// assign all props from DTO to metric: metric.setSmth(dto.getSmth())
// ...
List<DataSource> dsList = dto.getDataSourceIds().stream()
.map(dataSourceRepo::findOne)
.collect(Collectors.toList())
metric.setDataSources(dsList);
metricRepo.save(metric); // finally persist object
}
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