Java中Xml和实体互转

心已赠人 2024-03-23 15:41 61阅读 0赞

#### 文章目录 ####

*  Java中Xml和实体互转
 *   *  1. 工具类 JaxbUtil
     *  2. 实体转Xml演示
     *   *  2-1 实体类，Main方法中，含实体和Xml互转的测试代码
         *  2-2 生成的Xml结果
     *  3. \[Java中操作Xml，可参考我写的另一篇博客【更完整、使用推荐】\](https://blog.csdn.net/qq\_17847881/article/details/130855130)

## Java中Xml和实体互转 ##

### 1. 工具类 JaxbUtil ###

import java.io.StringReader;
    import java.io.StringWriter;
    import java.util.Collection;
    import java.util.concurrent.ConcurrentHashMap;
    import java.util.concurrent.ConcurrentMap;
    
    import javax.xml.bind.JAXBContext;
    import javax.xml.bind.JAXBElement;
    import javax.xml.bind.JAXBException;
    import javax.xml.bind.Marshaller;
    import javax.xml.bind.Unmarshaller;
    import javax.xml.bind.annotation.XmlAnyElement;
    import javax.xml.namespace.QName;
    
    import org.apache.commons.lang3.StringUtils;
    import org.apache.commons.lang3.Validate;
    import sun.awt.geom.AreaOp;
    
    public class JaxbUtil {
        
    
        @SuppressWarnings("rawtypes")
        private static ConcurrentMap<Class, JAXBContext> jaxbContexts = new ConcurrentHashMap<Class, JAXBContext>();
    
        /**
         * Java Object->Xml without encoding.
         */
        @SuppressWarnings("rawtypes")
        public static String toXml(Object root) {
        
            Class clazz = root.getClass();
            return toXml(root, clazz, null);
        }
    
        /**
         * Java Object->Xml with encoding.
         */
        @SuppressWarnings("rawtypes")
        public static String toXml(Object root, String encoding) {
        
            Class clazz = root.getClass();
            return toXml(root, clazz, encoding);
        }
    
        /**
         * Java Object->Xml with encoding.
         */
        @SuppressWarnings("rawtypes")
        public static String toXml(Object root, Class clazz, String encoding) {
        
            try {
        
                StringWriter writer = new StringWriter();
                createMarshaller(clazz, encoding).marshal(root, writer);
                return writer.toString();
            } catch (JAXBException e) {
        
                e.printStackTrace();
            }
            return null;
        }
    
        /**
         * Java Collection->Xml without encoding, 特别支持Root Element是Collection的情形.
         */
        @SuppressWarnings("rawtypes")
        public static String toXml(Collection<?> root, String rootName, Class clazz) {
        
            return toXml(root, rootName, clazz, null);
        }
    
        /**
         * Java Collection->Xml with encoding, 特别支持Root Element是Collection的情形.
         */
        @SuppressWarnings("rawtypes")
        public static String toXml(Collection<?> root, String rootName, Class clazz, String encoding) {
        
            try {
        
                CollectionWrapper wrapper = new CollectionWrapper();
                wrapper.collection = root;
    
                JAXBElement<CollectionWrapper> wrapperElement = new JAXBElement<CollectionWrapper>(new QName(rootName),
                        CollectionWrapper.class, wrapper);
    
                StringWriter writer = new StringWriter();
                createMarshaller(clazz, encoding).marshal(wrapperElement, writer);
    
                return writer.toString();
            } catch (JAXBException e) {
        
                e.printStackTrace();
            }
            return null;
        }
    
        /**
         * Xml->Java Object.
         */
        @SuppressWarnings("unchecked")
        public static <T> T fromXml(String xml, Class<T> clazz) {
        
            try {
        
                StringReader reader = new StringReader(xml);
                return (T) createUnmarshaller(clazz).unmarshal(reader);
            } catch (JAXBException e) {
        
                e.printStackTrace();
            }
            return null;
        }
    
        /**
         * 创建Marshaller并设定encoding(可为null).
         * 线程不安全，需要每次创建或pooling。
         */
        @SuppressWarnings("rawtypes")
        public static Marshaller createMarshaller(Class clazz, String encoding) {
        
            try {
        
                JAXBContext jaxbContext = getJaxbContext(clazz);
    
                Marshaller marshaller = jaxbContext.createMarshaller();
    
                marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
    
                if (StringUtils.isNotBlank(encoding)) {
        
                    marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);
                }
                return marshaller;
            } catch (JAXBException e) {
        
                e.printStackTrace();
            }
            return null;
        }
    
        /**
         * 创建UnMarshaller.
         * 线程不安全，需要每次创建或pooling。
         */
        @SuppressWarnings("rawtypes")
        public static Unmarshaller createUnmarshaller(Class clazz) {
        
            try {
        
                JAXBContext jaxbContext = getJaxbContext(clazz);
                return jaxbContext.createUnmarshaller();
            } catch (JAXBException e) {
        
                e.printStackTrace();
            }
            return null;
        }
    
        @SuppressWarnings("rawtypes")
        protected static JAXBContext getJaxbContext(Class clazz) {
        
            Validate.notNull(clazz, "'clazz' must not be null");
            JAXBContext jaxbContext = jaxbContexts.get(clazz);
            if (jaxbContext == null) {
        
                try {
        
                    jaxbContext = JAXBContext.newInstance(clazz, CollectionWrapper.class);
                    jaxbContexts.putIfAbsent(clazz, jaxbContext);
                } catch (JAXBException ex) {
        
                    throw new RuntimeException("Could not instantiate JAXBContext for class [" + clazz + "]: "
                            + ex.getMessage(), ex);
                }
            }
            return jaxbContext;
        }
    
        /**
         * 封装Root Element 是 Collection的情况.
         */
        public static class CollectionWrapper {
        
    
            @XmlAnyElement
            protected Collection<?> collection;
        }
    }

### 2. 实体转Xml演示 ###

#### 2-1 实体类，Main方法中，含实体和Xml互转的测试代码 ####

package com.ruoyi.system.controller;
    
    
    import com.alibaba.fastjson.JSON;
    
    import java.io.Serializable;
    import java.util.ArrayList;
    import java.util.List;
    
    import javax.xml.bind.annotation.XmlAccessType;
    import javax.xml.bind.annotation.XmlAccessorType;
    import javax.xml.bind.annotation.XmlElement;
    import javax.xml.bind.annotation.XmlRootElement;
    import javax.xml.bind.annotation.XmlTransient;
    
    
    //设置生成的xml的根节点的名称
    @XmlRootElement(name="sendHospitalInfo")
    //设置根据字段还是方法生成
    @XmlAccessorType(XmlAccessType.FIELD)
    public class Hospital implements Serializable {
        
        //xml节点的名称
        @XmlElement(name="hospitalId")
        private String hospitalid;
    
        //忽略此属性
        @XmlTransient
        private long id;
    
        @XmlElement(name="hospitalName")
        private String hospitalname;
    
        public String getHospitalid() {
        
            return hospitalid;
        }
    
        public void setHospitalid(String hospitalid) {
        
            this.hospitalid = hospitalid;
        }
    
        public long getId() {
        
            return id;
        }
    
        public void setId(long id) {
        
            this.id = id;
        }
    
        public String getHospitalname() {
        
            return hospitalname;
        }
    
        public void setHospitalname(String hospitalname) {
        
            this.hospitalname = hospitalname;
        }
    
        public static void main(String[] args) {
        
            Hospital sydw = new Hospital();
            sydw.setHospitalid("001");
            sydw.setHospitalname("hospital_name");
    
    
            Hospital sydw2 = new Hospital();
            sydw2.setHospitalid("002");
            sydw2.setHospitalname("hospital_name");
    
            List<Hospital> lists = new ArrayList<>();
            lists.add(sydw);
            lists.add(sydw2);
            Demo demo = new Demo();
            demo.setHospitals(lists);
            // 实体转xml
            System.out.println(JaxbUtil.toXml(demo));
            System.out.println(JaxbUtil.toXml(sydw));
    
            // xml 转实体
            Demo demo1 = new Demo();
            demo1=JaxbUtil.fromXml(JaxbUtil.toXml(demo),Demo.class);
            System.out.println(JSON.toJSONString(demo1));
        }
    }
    
    @XmlRootElement(name="sendHospitalInfoList")
    //设置根据字段还是方法生成
    @XmlAccessorType(XmlAccessType.FIELD)
    class Demo{
        
        private List<Hospital> hospitals;
    
        public List<Hospital> getHospitals() {
        
            return hospitals;
        }
    
        public void setHospitals(List<Hospital> hospitals) {
        
            this.hospitals = hospitals;
        }
    }

#### 2-2 生成的Xml结果 ####

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <sendHospitalInfoList>
        <hospitals>
            <hospitalId>001</hospitalId>
            <hospitalName>hospital_name</hospitalName>
        </hospitals>
        <hospitals>
            <hospitalId>002</hospitalId>
            <hospitalName>hospital_name</hospitalName>
        </hospitals>
    </sendHospitalInfoList>

### 3. [Java中操作Xml，可参考我写的另一篇博客【更完整、使用推荐】][Java_Xml] ###

[Java_Xml]: https://blog.csdn.net/qq_17847881/article/details/130855130