java object與xml的轉換

概述：之前對於XML與Java對象的轉換了解比較少，今天學微信接口API時恰好接觸到，因此就寫下來了，初學者望你們見諒哈。

1.既然是Java對象與XML的轉換，因此就須要有個Java類來得到對象，本例子主要涉及到BOY類和測試運行的類

2.代碼

 2.1 開始第一步的簡單學習

      

    @XmlRootElement

     @XmlAccessorType(XmlAccessType.FIELD)//field只是類上的字段，並非屬性

     public class Boy {

            String name = "xu**";

     }

    public class TestXml {

          public static void  main(String args[]){

              try {

                  JAXBContext jaxbContext = JAXBContext.newInstance(Boy.class);

                  Marshaller marshaller = jaxbContext.createMarshaller(); //將對象轉換成XML格式

                  Unmarshaller unmarshaller = jaxbContext.createUnmarshaller(); //將XML轉換成對象

                  Boy boy = new Boy();

                  marshaller.marshal(boy,System.out);//以打印輸出的形式顯示

                  System.out.println();

                  String xmlStr = "<boy><name>許**</name></boy>";

                  Boy towBoy = (Boy)unmarshaller.unmarshal(new StringReader(xmlStr));

                  System.out.println(towBoy.name);

              } catch (JAXBException e) {

                  e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

              }

          }

    }

      打印的結果是：

                <?xml version="1.0" encoding="UTF-8" standalone="yes"?><boy><name>xu**</name></boy>

                許**

    2.2 當boy變成下面這樣子

            @XmlRootElement

            @XmlAccessorType(XmlAccessType.PROPERTY)//property是屬性

            public class Boy {

                    String name = "xu**";

            }

             打印的結果是：

                    <?xml version="1.0" encoding="UTF-8" standalone="yes"?><boy/>

                    xu**

    2.3 想要有2.1的結果就須要提供name的get方法來得到屬性        

        @XmlRootElement

        @XmlAccessorType(XmlAccessType.PROPERTY)

        public class Boy {

            String name ="123";

            public String getName() {

                return name;

            }        

            public void setName(String name) {

                this.name = name;

            }

        }

    2.4 也能夠經過xmlelement註解

         @XmlRootElement

            @XmlAccessorType(XmlAccessType.PROPERTY)

            public class Boy {

                String name ="123";

                @XmlElement

                Integer age = 10;

                public String getName() {

                    return name;

                }

                public void setName(String name) {

                    this.name = name;

                }

            }

            打印的結果是：

                <?xml version="1.0" encoding="UTF-8" standalone="yes"?><boy><age>10</age><name>123</name></boy>

                許**

        2.5 同時也能夠將BOY改標籤，並放在一個命名空間下           

            @XmlRootElement (name = "xu",namespace = "http://test")

            @XmlAccessorType(XmlAccessType.PROPERTY)

            public class Boy {

                @XmlElement

                String name ="123";

                @XmlElement

                Integer age = 10;

            

            }

           public class TestXml {

                  public static void  main(String args[]){

                      try {

                          JAXBContext jaxbContext = JAXBContext.newInstance(Boy.class);

                          Marshaller marshaller = jaxbContext.createMarshaller(); //將對象轉換成XML格式

                          Unmarshaller unmarshaller = jaxbContext.createUnmarshaller(); //將XML轉換成對象

                          Boy boy = new Boy();

                          marshaller.marshal(boy,System.out);

                          System.out.println();

                          String xmlStr = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?><ns2:xu xmlns:ns2=\"http://test\"><name>許**</name><age>25</age></ns2:xu>";

                          Boy towBoy = (Boy)unmarshaller.unmarshal(new StringReader(xmlStr));

                          System.out.println(towBoy.name);

                          System.out.println(towBoy.age);

                      } catch (JAXBException e) {

                          e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

                      }

                  }

            }

            打印的結果是：

                <?xml version="1.0" encoding="UTF-8" standalone="yes"?><ns2:xu xmlns:ns2="http://test"><name>123</name><age>10</age></ns2:xu>

                許**

                25

  
            2.6   @XmlJavaTypeAdaptor

            @XmlRootElement (name = "xu",namespace = "http://test")

            @XmlAccessorType(XmlAccessType.PROPERTY)

            public class Boy {

                @XmlElement

                String name ="許**";

                @XmlElement

                Integer age = 25; 

               private TestXmlInterface testXmlInterface;          

            }

              咱們要多寫一個類TestXmlInterfaceAdaptor用來返回TestXmlInterface 的一個具體實現類的推向

              在轉換成XML時接口TestXmlInterface 沒法被轉換，咱們得加上@XmlJavaTypeAdaptor(TestXmlInterfaceAdaptor.class)