问题描述
使用JAXB时,我想在使用泛型时从我的XML元素中删除多余的名称空间/类型。我该怎么做,或者我做错了什么?我希望使用泛型,这样我只需编写一段代码即可。
示例代码:
public static void main(String [] args){
try {
TestRoot root = new TestRoot();
root.name.value =bobby;
root.age.value = 102;
root.color.value =blue;
JAXBContext context = JAXBContext.newInstance(root.getClass());
Marshaller marsh = context.createMarshaller();
marsh.setProperty(Marshaller.JAXB_ENCODING,UTF-8);
marsh.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT,Boolean.TRUE);
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
marsh.marshal(root,pw);
System.out.println(sw.toString());
}
catch(Throwable t){
t.printStackTrace();
@XmlRootElement
static class TestRoot {
@XmlElement public TestGeneric< String> name = new TestGeneric< String>(true);
@XmlElement public TestGeneric< Integer> age = new TestGeneric< Integer>(true);
@XmlElement public TestWhatIWouldLike color = new TestWhatIWouldLike(true);
}
@XmlAccessorType(XmlAccessType.NONE)
静态类TestGeneric< T> {
@XmlAttribute public boolean isRequired;
@XmlElement公共T值;
$ b $ public TestGeneric(){
}
public TestGeneric(boolean isRequired){
this.isRequired = isRequired;
$ b @XmlAccessorType(XmlAccessType.NONE)
静态类TestWhatIWouldLike {
@XmlAttribute public boolean isRequired;
@XmlElement public String value;
$ b $ public TestWhatIWouldLike(){
}
public TestWhatIWouldLike(boolean isRequired){
this.isRequired = isRequired;
$ / code $ / pre
$ b $输出:
<?xml version =1.0encoding =UTF-8standalone =yes?>
< testRoot>
< name isRequired =true>
<值xsi:type =xs:stringxmlns:xs =http://www.w3.org/2001/XMLSchemaxmlns:xsi =http://www.w3.org/ 2001 / XMLSchema的实例>发夹< /值GT;
< / name>
< age isRequired =true>
<值xsi:type =xs:intxmlns:xs =http://www.w3.org/2001/XMLSchemaxmlns:xsi =http://www.w3.org/ 2001 / XMLSchema的实例> 102< /值GT;
< / age>
< color isRequired =true>
<值>蓝色< /值>
< / color>
< / testRoot>
解决方案Test Generic 您的JAXB(JSR-222)实现将为每个类创建映射(即 TestGeneric ,而不是类型(即 TestGeneric< Integer> )。因此,它会将值字段视为类型 Object 这会导致 xsi:type 属性,因为您的JAXB实现正在添加足够的信息来解组相同的类型。
@XmlAccessorType(XmlAccessType.NONE)
静态类TestGeneric< T> {
@XmlAttribute public boolean isRequired;
@XmlElement public T value;
$ b $ public TestGeneric(){
}
$ b $ public TestGeneric(boolean isRequired){
this.isRequired = isRequired;
}
}
演示
以下是您可以采用的方法我已经引入了 TestGeneric 的子类来表示不同的可能类型。
包论坛11192623;
import java.io.PrintWriter;
import java.io.StringWriter;
import javax.xml.bind。*;
import javax.xml.bind.annotation。*;
public class Demo {
public static void main(String [] args){
try {
TestRoot root = new TestRoot();
root.name.value =bobby;
root.age.value = 102;
root.color.value =blue;
JAXBContext context = JAXBContext.newInstance(root.getClass());
Marshaller marsh = context.createMarshaller();
marsh.setProperty(Marshaller.JAXB_ENCODING,UTF-8);
marsh.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT,Boolean.TRUE);
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
marsh.marshal(root,pw);
System.out.println(sw.toString());
}
catch(Throwable t){
t.printStackTrace();
@XmlRootElement
static class TestRoot {
@XmlElement public TestString name = new TestString(true);
@XmlElement public TestInteger age = new TestInteger(true);
@XmlElement public TestString color = new TestString(true);
$ b @XmlAccessorType(XmlAccessType.NONE)
@XmlTransient
@XmlSeeAlso({TestInteger.class,TestString.class})
静态类TestGeneric< ; T> {
@XmlAttribute
public boolean isRequired;
公共T值;
$ b $ public TestGeneric(){
}
public TestGeneric(boolean isRequired){
this.isRequired = isRequired;
}
}
static class TestInteger extends TestGeneric< Integer> {
public TestInteger(){
}
public TestInteger(boolean b){
super(b);
}
@XmlElement
public Integer getValue(){
返回值;
}
public void setValue(Integer value){
this.value = value;
}
}
静态类TestString extends TestGeneric< String> {
public TestString(){
}
public TestString(boolean b){
super(b);
}
@XmlElement
public String getValue(){
返回值;
}
public void setValue(String value){
this.value = value;
}
}
}
When using JAXB, I'd like to remove the excess namespaces/types from my XML elements when using Generics. How can I do this or what am I doing wrong? I'd like to use Generics so that I only have to write a block of code once.
Example code:
public static void main(String[] args) { try { TestRoot root = new TestRoot(); root.name.value = "bobby"; root.age.value = 102; root.color.value = "blue"; JAXBContext context = JAXBContext.newInstance(root.getClass()); Marshaller marsh = context.createMarshaller(); marsh.setProperty(Marshaller.JAXB_ENCODING,"UTF-8"); marsh.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT,Boolean.TRUE); StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw); marsh.marshal(root,pw); System.out.println(sw.toString()); } catch(Throwable t) { t.printStackTrace(); } } @XmlRootElement static class TestRoot { @XmlElement public TestGeneric<String> name = new TestGeneric<String>(true); @XmlElement public TestGeneric<Integer> age = new TestGeneric<Integer>(true); @XmlElement public TestWhatIWouldLike color = new TestWhatIWouldLike(true); } @XmlAccessorType(XmlAccessType.NONE) static class TestGeneric<T> { @XmlAttribute public boolean isRequired; @XmlElement public T value; public TestGeneric() { } public TestGeneric(boolean isRequired) { this.isRequired = isRequired; } } @XmlAccessorType(XmlAccessType.NONE) static class TestWhatIWouldLike { @XmlAttribute public boolean isRequired; @XmlElement public String value; public TestWhatIWouldLike() { } public TestWhatIWouldLike(boolean isRequired) { this.isRequired = isRequired; } }Output:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <testRoot> <name isRequired="true"> <value xsi:type="xs:string" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">bobby</value> </name> <age isRequired="true"> <value xsi:type="xs:int" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">102</value> </age> <color isRequired="true"> <value>blue</value> </color> </testRoot>解决方案Test Generic
Your JAXB (JSR-222) implementation is going to create mappings per class (i.e. TestGeneric, not type (i.e. TestGeneric<Integer>). As such it is going to treat the value field as type Object. This will result in the xsi:type attributes as your JAXB implementation is adding enough information to be able to unmarshal the same types.
@XmlAccessorType(XmlAccessType.NONE) static class TestGeneric<T> { @XmlAttribute public boolean isRequired; @XmlElement public T value; public TestGeneric() { } public TestGeneric(boolean isRequired) { this.isRequired = isRequired; } }Demo
Below is an approach you could use. I have introduced subclasses of TestGeneric to represent the different possible types.
package forum11192623; import java.io.PrintWriter; import java.io.StringWriter; import javax.xml.bind.*; import javax.xml.bind.annotation.*; public class Demo { public static void main(String[] args) { try { TestRoot root = new TestRoot(); root.name.value = "bobby"; root.age.value = 102; root.color.value = "blue"; JAXBContext context = JAXBContext.newInstance(root.getClass()); Marshaller marsh = context.createMarshaller(); marsh.setProperty(Marshaller.JAXB_ENCODING,"UTF-8"); marsh.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT,Boolean.TRUE); StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw); marsh.marshal(root,pw); System.out.println(sw.toString()); } catch(Throwable t) { t.printStackTrace(); } } @XmlRootElement static class TestRoot { @XmlElement public TestString name = new TestString(true); @XmlElement public TestInteger age = new TestInteger(true); @XmlElement public TestString color = new TestString(true); } @XmlAccessorType(XmlAccessType.NONE) @XmlTransient @XmlSeeAlso({TestInteger.class, TestString.class}) static class TestGeneric<T> { @XmlAttribute public boolean isRequired; public T value; public TestGeneric() { } public TestGeneric(boolean isRequired) { this.isRequired = isRequired; } } static class TestInteger extends TestGeneric<Integer> { public TestInteger() { } public TestInteger(boolean b) { super(b); } @XmlElement public Integer getValue() { return value; } public void setValue(Integer value) { this.value = value; } } static class TestString extends TestGeneric<String> { public TestString() { } public TestString(boolean b) { super(b); } @XmlElement public String getValue() { return value; } public void setValue(String value) { this.value = value; } } }
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