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JAXB2实现JavaBean与XML互转

1. JAXB2工具类

1.1 工具类概述

在JAXB2（Java API for XML Binding）中，工具类是实现JavaBean与XML互转的核心。通过自定义工具类，可以方便地将Java对象转换为XML格式，或者从XML解析出Java对象。以下是我们自定义的JAXB2工具类。

1.2 JaxbUtil工具类

package com.example.springsecuritydemo.jaxb2;
import java.io.StringReader;
import java.io.StringWriter;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
/**
 * JAXB2工具类
 * @author swq
 * @create 2021-04-19 21:46
 */
public class JaxbUtil {
    /* 将JavaBean转换为XML，默认编码为UTF-8 */
    public static String convertToXml(Object obj) {
        return convertToXml(obj, "UTF-8");
    }
    /* 将JavaBean转换为XML，指定编码 */
    public static String convertToXml(Object obj, String encoding) {
        String result = null;
        try {
            JAXBContext context = JAXBContext.newInstance(obj.getClass());
            Marshaller marshaller = context.createMarshaller();
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
            marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);
            StringWriter writer = new StringWriter();
            marshaller.marshal(obj, writer);
            result = writer.toString();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
    /* 将XML转换为JavaBean */
    public static 
   
     T convertToJavaBean(String xml, Class
    
      c) {
        T t = null;
        try {
            JAXBContext context = JAXBContext.newInstance(c);
            Unmarshaller unmarshaller = context.createUnmarshaller();
            t = (T) unmarshaller.unmarshal(new StringReader(xml));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return t;
    }
}
    
   

2. 测试类

2.1 测试类概述

为了验证工具类的功能，我们创建了一系列测试类。这些测试类涵盖了JavaBean与XML互转的主要场景，包括单个对象转换、复杂对象转换以及包含嵌套结构的转换。

2.2 测试用例

测试用例1：简单JavaBean转换

@Test
public void showMarshaller() {
    Book book = new Book();
    book.setId(100);
    book.setAuthor("James");
    book.setCalendar(new Date());
    book.setPrice(23.45f);
    String str = JaxbUtil.convertToXml(book);
    System.out.println(str);
}

测试用例2：复杂JavaBean转换

@Test
public void showUnMarshaller() {
    String str = "
   
  
   " +
                "
   
  
   
    
    " +
                "    
    
    
    
     
     James
     
    
    " +
                "   
    
    
    
     
     2013-03-29T09:25:56.004+08:00
     
    
    " +
                "  
    
    
    
     
     23.45
     
    
    " +
                "
    
   
   ";
    Book book = JaxbUtil.convertToJavaBean(str, Book.class);
    System.out.println(book);
}

3. 实体类

3.1 Book实体类

package com.example.springsecuritydemo.jaxb2;
import lombok.Data;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlType;
@Data
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "book")
@XmlType(name = "book", propOrder = { "author", "calendar", "price", "id" })
public class Book {
    @XmlElement(required = true)
    private String author;
    @XmlElement(name = "price_1", required = true)
    private float price;
    @XmlElement
    private Date calendar;
    @XmlAttribute
    private Integer id;
}

3.2 Country实体类

package com.example.springsecuritydemo.jaxb2;
import lombok.Data;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlRootElement;
@Data
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "country")
public class Country {
    @XmlElement(name = "country_name")
    private String name;
    @XmlElementWrapper(name = "provinces")
    @XmlElement(name = "province")
    private List
   
     provinceList;
}
   

3.3 Province实体类

package com.example.springsecuritydemo.jaxb2;
import lombok.Data;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlType;
@Data
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(propOrder = { "name", "provCity" })
public class Province {
    @XmlElement(name = "province_name")
    private String name;
    @XmlElement(name = "prov_city")
    private String provCity;
}

3.4 Role实体类

package com.example.springsecuritydemo.jaxb2;
import lombok.Data;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlType;
@Data
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(propOrder = { "name", "desc" })
public class Role {
    @XmlElement
    private String name;
    @XmlElement
    private String desc;
}

3.5 Student实体类

package com.example.springsecuritydemo.jaxb2;
import lombok.Data;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
@Data
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "student")
public class Student {
    @XmlAttribute
    private Integer id;
    @XmlElement
    private String name;
    @XmlElement(name = "role")
    private Role role;
}

通过以上JAXB2工具类和实体类，您可以轻松实现JavaBean与XML之间的互转。工具类支持多种编码格式，并且提供了详细的错误处理机制，确保转换过程的稳定性和可靠性。