如何使用JAXB将长属性作为JSON字符串值返回 [英] How to return a long property as JSON string value with JAXB

问题描述

我有一个用 @XmlRootElement 注释的Java类。这个Java类有一个long属性（ private long id ），我希望它返回给JavaScript-client。

I have a Java class annotated with @XmlRootElement. This Java class has a long property (private long id) that I want to return to a JavaScript-client.

我按如下方式创建JSON：

I create the JSON as follows:

MyEntity myInstance = new MyEntity("Benny Neugebauer", 2517564202727464120);
StringWriter writer = new StringWriter();
JSONConfiguration config = JSONConfiguration.natural().build();
Class[] types = {MyEntity.class};
JSONJAXBContext context = new JSONJAXBContext(config, types);
JSONMarshaller marshaller = context.createJSONMarshaller();
marshaller.marshallToJSON(myInstance, writer);
json = writer.toString();
System.out.println(writer.toString());

这将生成：

{"name":"Benny Neugebauer","id":2517564202727464120}

但问题是JavaScript客户端的长值太大了。因此，我想将此值作为字符串返回（不要在Java中将long作为字符串）。

But the problem is that the long value is too large for the JavaScript client. Therefore, I would like to return this value as a string (without making the long a string in Java).

是否有可以生成的注释（或类似的东西）以下？

Is there an annotation (or something similar) that can generate the following?

{"name":"Benny Neugebauer","id":"2517564202727464120"}

推荐答案

注意：我是 EclipseLink JAXB（MOXy） 领导和 JAXB（JSR-222） 专家组。

Note: I'm the EclipseLink JAXB (MOXy) lead and a member of the JAXB (JSR-222) expert group.

以下是如何使用MOXy作为JSON提供程序来完成此用例。

Below is how you could accomplish this use case with MOXy as your JSON provider.

MyEntity

您可以使用 @XmlSchemaType（name =string）<注释 long 属性表示它应该被编组为字符串。

package forum11737597;

import javax.xml.bind.annotation.*;

@XmlRootElement
public class MyEntity {

    private String name;
    private long id;

    public MyEntity() {
    }

    public MyEntity(String name, long id) {
        setName(name);
        setId(id);
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @XmlSchemaType(name="string")
    public long getId() {
        return id;
    }

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

}

jaxb.properties

要将MOXy配置为JAXB提供程序，您需要在文件中包含一个名为 jaxb.properties 的文件。与您的域模型相同的包（请参阅： http：// blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html ）。

To configure MOXy as your JAXB provider you need to include a file called jaxb.properties in the same package as your domain model (see: http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html).

javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory

演示

我修改了示例代码，以显示使用MOXy时的样子。

I have modified your sample code to show what it would look like if you used MOXy.

package forum11737597;

import java.io.StringWriter;
import java.util.*;
import javax.xml.bind.*;
import org.eclipse.persistence.jaxb.JAXBContextProperties;

public class Demo {

    public static void main(String[] args) throws Exception {
        MyEntity myInstance = new MyEntity("Benny Neugebauer", 2517564202727464120L);
        StringWriter writer = new StringWriter();
        Map<String, Object> config = new HashMap<String, Object>(2);
        config.put(JAXBContextProperties.MEDIA_TYPE, "application/json");
        config.put(JAXBContextProperties.JSON_INCLUDE_ROOT, false);
        Class[] types = {MyEntity.class};
        JAXBContext context = JAXBContext.newInstance(types, config);
        Marshaller marshaller = context.createMarshaller();
        marshaller.marshal(myInstance, writer);
        System.out.println(writer.toString());
    }

}

输出

以下是运行演示代码的输出：

Below is the output from running the demo code:

{"id":"2517564202727464120","name":"Benny Neugebauer"}

更多信息

• http://blog.bdoughan.com/2011/08/json-binding-with-eclipselink-moxy.html

• http://blog.bdoughan.com/2011/08/json-binding-with-eclipselink-moxy.html

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