Spring Rest -> Hibernate 实体到 JSON
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【中文标题】Spring Rest -> Hibernate 实体到 JSON【英文标题】：Spring Rest -> Hibernate entity to JSON 【发布时间】：2019-03-27 22:15:48 【问题描述】：我正在使用 spring 框架创建 REST API。我的实体基于一张表，REST API 应该使用具有以下 JSON 结构的 POST 操作来调用。有人可以解释一下如何映射实体类，以便它可以使用下面显示的 json。 由于我的实体仅基于一个表，我无法理解它如何为相同的表属性创建嵌套的 json 对象。
"process_ar_receipt":
"message_header":
"source_system_guid": "DDED-DBCD-REV-E1F4343DB3434",
"source_system": "MeSo_TravelAds"
,
"receipt_header":
"customer_number": "123",
"source_receipt_number": "TESTRCPT_1523",
【问题讨论】：
为什么不使用 DTO 并将所需字段映射到代码中的实体类？另一种方法是创建自定义反序列化器。仅使用注释和平面域对象结构是不可能的。 我是 Spring 框架的新手。你是说我应该在 REST 控制器中获取整个 JSON 对象并手动读取所有 JSON 字段并将它们设置到实体 pojo 中。 查看杰克逊库。它将允许您将传入的 json 文件转换为 POJO，然后您可以随心所欲地使用该 pojo 来休眠实体 【参考方案1】：您可以使用 Gson 将 json 转换为 DTO
https://jarroba.com/gson-json-java-ejemplos/
【讨论】：
【参考方案2】：伪代码 假设您的实体类为
@Entity(name="foo")
class Data
@Id
private String source_system_guid;
@Column
private String source_system;
@Column
private String customer_number;
@Column
private String source_receipt_number;
public Data()
public Data(String ssId, String sourceSystm, String custNum, String srcRcptNum)
this.source_system_guid = ssId;
this.source_system = sourceSystm;
this.customer_number = custNum;
this.source_receipt_number = srcRcptNum;
public String getSource_system_guid()
return source_system_guid;
public void setSource_system_guid(String source_system_guid)
this.source_system_guid = source_system_guid;
public String getSource_system()
return source_system;
public void setSource_system(String source_system)
this.source_system = source_system;
public String getCustomer_number()
return customer_number;
public void setCustomer_number(String customer_number)
this.customer_number = customer_number;
public String getSource_receipt_number()
return source_receipt_number;
public void setSource_receipt_number(String source_receipt_number)
this.source_receipt_number = source_receipt_number;
现在，由于您的 DTO/BO 即数据传输对象或业务对象与实际实体不同，我们将创建所需的 BO 对象，如下所示
class DataTO
@JsonProperty("process_ar_receipt")
private ReceiptTO receiptTO=new ReceiptTO();
public ReceiptTO getReceiptTO()
return receiptTO;
public void setReceiptTO(ReceiptTO receiptTO)
this.receiptTO = receiptTO;
class ReceiptTO
@JsonProperty("message_header")
private MessageHeader messageHeder = new MessageHeader();
@JsonProperty("receipt_header")
private ReceiptHeader receiptHeder = new ReceiptHeader();
public MessageHeader getMessageHeder()
return messageHeder;
public void setMessageHeder(MessageHeader messageHeder)
this.messageHeder = messageHeder;
public ReceiptHeader getReceiptHeder()
return receiptHeder;
public void setReceiptHeder(ReceiptHeader receiptHeder)
this.receiptHeder = receiptHeder;
class MessageHeader
@JsonProperty("source_System_Guid")
private String sourceSystemId;
@JsonProperty("system_Id")
private String systemId;
public String getSourceSystemId()
return sourceSystemId;
public void setSourceSystemId(String sourceSystemId)
this.sourceSystemId = sourceSystemId;
public String getSystemId()
return systemId;
public void setSystemId(String systemId)
this.systemId = systemId;
class ReceiptHeader
@JsonProperty("customer_number")
private String customerNumber;
@JsonProperty("source_rcpt_number")
private String sourceReceiptNumber;
public String getCustomerNumber()
return customerNumber;
public void setCustomerNumber(String customerNumber)
this.customerNumber = customerNumber;
public String getSourceReceiptNumber()
return sourceReceiptNumber;
public void setSourceReceiptNumber(String sourceReceiptNumber)
this.sourceReceiptNumber = sourceReceiptNumber;
@JsonProperty 注解是从 org.codehaus.jackson.annotate.JsonProperty 导入的；即来自杰克逊罐
现在是一个简单的测试类来演示 DTO/BO 来回实体转换
public class Test
public static void main(String[] args) throws JsonGenerationException, JsonMappingException, IOException
List<Data> datas = new ArrayList<Data>();
datas.add(new Data("DDED-DBCD-REV-E1F4343DB3434","MeSo_TravelAds","123","TESTRCPT_1523"));
datas.add(new Data("ADED-EWQD-REV-E1F4343YG3434","FooSo_MusicAds","132","TESTRCPT_1523"));
datas.add(new Data("YDED-YUTR-REV-E1F43UIDB3434","BarSo_HealthAds","143","TESTRCPT_1523"));
List<DataTO> dataTOs = new ArrayList<DataTO>();
for (Data data : datas)
DataTO dataTO = new DataTO();
dataTO.getReceiptTO().getMessageHeder().setSourceSystemId(data.getSource_system_guid());
dataTO.getReceiptTO().getMessageHeder().setSystemId(data.getSource_system());
dataTO.getReceiptTO().getReceiptHeder().setCustomerNumber(data.getCustomer_number());
dataTO.getReceiptTO().getReceiptHeder().setSourceReceiptNumber(data.getSource_receipt_number());
dataTOs.add(dataTO);
ObjectMapper mapper = new ObjectMapper();
String str = mapper.writeValueAsString(dataTOs);
System.out.println(str);
这将为您提供以下结果
[
"process_ar_receipt":
"message_header":
"source_System_Guid":"DDED-DBCD-REV-E1F4343DB3434",
"system_Id":"MeSo_TravelAds"
,
"receipt_header":
"customer_number":"123",
"source_rcpt_number":"TESTRCPT_1523"
,
"process_ar_receipt":
"message_header":
"source_System_Guid":"ADED-EWQD-REV-E1F4343YG3434",
"system_Id":"FooSo_MusicAds"
,
"receipt_header":
"customer_number":"132",
"source_rcpt_number":"TESTRCPT_1523"
,
"process_ar_receipt":
"message_header":
"source_System_Guid":"YDED-YUTR-REV-E1F43UIDB3434",
"system_Id":"BarSo_HealthAds"
,
"receipt_header":
"customer_number":"143",
"source_rcpt_number":"TESTRCPT_1523"
]
与其他转换类似
String input = " \r\n" +
" \"process_ar_receipt\": \r\n" +
" \"message_header\": \r\n" +
" \"source_System_Guid\":\"ADED-EWQD-REV-E1F4343YG3434\",\r\n" +
" \"system_Id\":\"FooSo_MusicAds\"\r\n" +
" ,\r\n" +
" \"receipt_header\": \r\n" +
" \"customer_number\":\"132\",\r\n" +
" \"source_rcpt_number\":\"TESTRCPT_1523\"\r\n" +
" \r\n" +
" \r\n" +
" ";
DataTO dataTO = mapper.readValue(input, DataTO.class);
System.out.println(dataTO.getReceiptTO().getMessageHeder().getSourceSystemId());
System.out.println(dataTO.getReceiptTO().getMessageHeder().getSystemId());
System.out.println(dataTO.getReceiptTO().getReceiptHeder().getCustomerNumber());
System.out.println(dataTO.getReceiptTO().getReceiptHeder().getSourceReceiptNumber());
这将打印出来
ADED-EWQD-REV-E1F4343YG3434
FooSo_MusicAds
132
TESTRCPT_1523
您不必使用映射器代码，您可以直接将杰克逊转换器添加为 HttpMessageConverted，它将自动将 JSON 转换为 java 对象
@Configuration
@EnableWebMvc
public class WebConfiguration extends WebMvcConfigurerAdapter
... other configurations
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters)
Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
builder.serializationInclusion(JsonInclude.Include.NON_NULL);
builder.propertyNamingStrategy(PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES);
builder.serializationInclusion(Include.NON_EMPTY);
builder.indentOutput(true).dateFormat(new SimpleDateFormat("yyyy-MM-dd"));
converters.add(new MappingJackson2HttpMessageConverter(builder.build()));
converters.add(new MappingJackson2XmlHttpMessageConverter(builder.createXmlMapper(true).build()));
【讨论】：
@Anuj 让我知道，如果您需要对该主题进行更多说明，我可以通过查看您的实体类来分享更多详细信息以上是关于Spring Rest -> Hibernate 实体到 JSON的主要内容，如果未能解决你的问题，请参考以下文章
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