对象和xml之间的转化--XStream的使用

ゝ一世哀愁。 2022-01-23 02:29 367阅读 0赞

# 对象和xml之间的转化 #

在项目开发中有时候与其他第三方接口对接需要用到,参数和响应有时候会以xml的形式传递

需要导入的依赖是 pom

<dependency>
                <groupId>com.thoughtworks.xstream</groupId>
                <artifactId>xstream</artifactId>
                <version>1.4.10</version>
            </dependency>

### 相关工具类的 ###

**XStreamFactory**

import com.thoughtworks.xstream.XStream;
    import com.thoughtworks.xstream.annotations.XStreamAlias;
    import com.thoughtworks.xstream.core.util.QuickWriter;
    import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
    import com.thoughtworks.xstream.io.naming.NameCoder;
    import com.thoughtworks.xstream.io.naming.NoNameCoder;
    import com.thoughtworks.xstream.io.xml.PrettyPrintWriter;
    import com.thoughtworks.xstream.io.xml.XppDomDriver;
    import com.thoughtworks.xstream.security.AnyTypePermission;
    
    import java.io.Writer;
    import java.lang.reflect.Field;
    
    public class XStreamFactory {
        public static final String CDATA_PREFIX = "<![CDATA[";
        public static final String CDATA_SUFFIX = "]]>";
        public static XStream getXStream() {
            final NameCoder nameCoder = new NoNameCoder();
            XStream xStream = new XStream(new XppDomDriver(nameCoder) {
                @Override
                public HierarchicalStreamWriter createWriter(Writer out) {
                    return new PrettyPrintWriter(out, nameCoder) {
                        boolean cdataFlag = false;
                        Class<?> targetClass = null;
                        @Override
                        public void startNode(String name, Class clazz) {
                            super.startNode(name, clazz);
                            if (targetClass == null) {
                                targetClass = clazz;
                            }
                            cdataFlag = isCDATA(targetClass, name);
                        }
                        @Override
                        public void writeText(QuickWriter writer, String text) {
                            if (cdataFlag) {
                                writer.write(CDATA_PREFIX);
                                writer.write(text);
                                writer.write(CDATA_SUFFIX);
                            } else {
                                writer.write(text);
                            }
                        }
                    };
                }
            });
    
            // 设置默认的安全校验
            XStream.setupDefaultSecurity(xStream);
            // 使用本地的类加载器
            xStream.setClassLoader(XmlUtils.class.getClassLoader());
            // 允许所有的类进行转换
            xStream.addPermission(AnyTypePermission.ANY);
            return xStream;
        }
        private static boolean isCDATA(Class<?> clazz, String fieldAlias) {
            //检查类本身
            boolean cdataFlag = isExistCDATA(clazz, fieldAlias);
            if (cdataFlag) {
                return cdataFlag;
            }
            //继续检查父类
            Class<?> superClazz = clazz.getSuperclass();
            while (!superClazz.equals(Object.class)) {
                cdataFlag = isExistCDATA(superClazz, fieldAlias);
                if (cdataFlag) {
                    return cdataFlag;
                }
                superClazz = superClazz.getClass().getSuperclass();
            }
            return false;
        }
        /**
         * 检查是否有 @XStreamCDATA 注解
         * @param clazz clazz
         * @param fieldAlias fieldAlias
         * @return
         */
        private static boolean isExistCDATA(Class<?> clazz, String fieldAlias) {
            Field[] fields = clazz.getDeclaredFields();
            for (Field field : fields) {
                if (field.getAnnotation(XStreamCDATA.class) != null) {
                    XStreamAlias xStreamAlias = field.getAnnotation(XStreamAlias.class);
                    if (xStreamAlias != null && fieldAlias.equals(xStreamAlias.value())) {
                        return true;
                    } else {
                        if (fieldAlias.equals(field.getName())) {
                            return true;
                        }
                    }
                }
            }
            return false;
        }
    }

**XStreamCDATA** 这个注解是为了处理xml的内容需要添加<!\[CDATA\[\]>

import java.lang.annotation.ElementType;
    import java.lang.annotation.Retention;
    import java.lang.annotation.RetentionPolicy;
    import java.lang.annotation.Target;
    
    @Retention(RetentionPolicy.RUNTIME)
    @Target(ElementType.FIELD)
    public @interface XStreamCDATA {
    }

**XmlUtils**

import com.thoughtworks.xstream.XStream;
    import com.thoughtworks.xstream.io.xml.DomDriver;
    import com.thoughtworks.xstream.mapper.MapperWrapper;
    import com.thoughtworks.xstream.security.AnyTypePermission;
    import org.apache.commons.lang3.StringUtils;
    
    public class XmlUtils {
        private static String XML_TAG = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
        private static final String OBJ = "obj";
    
        private static final XStream xStream = XStreamFactory.getXStream();
    
        /**
         * 对象转xml
         *
         * @param obj 对象
         * @return
         */
        public static String toXml(Object obj) {
            xStream.processAnnotations(obj.getClass());
            //如果生成的是Objec不显示class属性
            xStream.aliasSystemAttribute(null, "class");
            return XML_TAG + xStream.toXML(obj);
        }
         /**
         * 定制化需求 特殊处理XStream对象
         * @return
         */
        private static XStream getInstance() {
            XStream xStream = new XStream(new DomDriver("UTF-8")) {
                /**
                 * 忽略xml中多余字段
                 */
                @Override
                protected MapperWrapper wrapMapper(MapperWrapper next) {
                    return new MapperWrapper(next) {
                        @SuppressWarnings("rawtypes")
                        @Override
                        public boolean shouldSerializeMember(Class definedIn, String fieldName) {
                            if (definedIn == Object.class) {
                                return false;
                            }
                            return super.shouldSerializeMember(definedIn, fieldName);
                        }
                    };
                }
            };
    
            // 设置默认的安全校验
            XStream.setupDefaultSecurity(xStream);
            // 使用本地的类加载器
            xStream.setClassLoader(XmlUtils.class.getClassLoader());
            // 允许所有的类进行转换
            xStream.addPermission(AnyTypePermission.ANY);
            return xStream;
        }
        
        /**
         * xml 转 bean
         *
         * @param xml
         * @param clazz
         * @param <T>
         * @return
         */
        public static <T> T xmlToBean(String xml, Class<T> clazz) {
            XStream instance = getInstance();
            instance.processAnnotations(clazz);
            instance.autodetectAnnotations(true);
            T obj = (T) instance.fromXML(xml);
            return obj;
        }
        
    }

### 测试对象 ###

**TestDemo**

import com.gyjx.outgateway.modle.request.UserNumber;
    import com.thoughtworks.xstream.annotations.XStreamAlias;
    
    @XStreamAlias("root")
    public class TestDemo {
    
        @XStreamAlias("UserNumber")
        private String userNumber;
    
        @XStreamAlias("name")
      //  @XStreamCDATA
        private String name;
    
        @XStreamAlias("Record")
        private UserNumber record;
    
    
        public TestDemo() {
        }
    
        public String getUserNumber() {
            return userNumber;
        }
    
        public void setUserNumber(String userNumber) {
            this.userNumber = userNumber;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public UserNumber getRecord() {
            return record;
        }
    
        public void setRecord(UserNumber record) {
            this.record = record;
        }
    
        @Override
        public String toString() {
            return "TestDemo{" +
                    "userNumber='" + userNumber + '\'' +
                    ", name='" + name + '\'' +
                    ", record=" + record +
                    '}';
        }
    }

**UserNumber**

import com.thoughtworks.xstream.annotations.XStreamAlias;
    
    @XStreamAlias("Record")
    public class UserNumber {
    
        @XStreamAlias("UserNumber")
        private String userNumber;
    
        public UserNumber() {
        }
    
        public String getUserNumber() {
            return userNumber;
        }
    
        public void setUserNumber(String userNumber) {
            this.userNumber = userNumber;
        }
    
        @Override
        public String toString() {
            return "UserNumber{" +
                    "userNumber='" + userNumber + '\'' +
                    '}';
        }
    }

### 对象与xml相互转化 ###

@Test
        public void testXml(){
    
            TestDemo testDemo = new TestDemo();
            testDemo.setName("qiuwei");
            testDemo.setUserNumber("13298878771");
            
            UserNumber userNumber = new UserNumber();
            userNumber.setUserNumber("17611013092");
            testDemo.setRecord(userNumber);
    
            //对象-->xml
            String s = XmlUtils.toXml(testDemo);
            System.out.println(s);
    
            System.out.println("===============================");
            //xml-->对象
            TestDemo testDemo1 = XmlUtils.xmlToBean(s, TestDemo.class);
    
            System.out.println(testDemo1.toString());
        }

测试结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTAyODk0_size_16_color_FFFFFF_t_70]

### 如何优雅处理<!\[CDATA\[\]> ###

在需要转化的属性上添加 @XStreamCDATA 注解  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTAyODk0_size_16_color_FFFFFF_t_70 1]

测试结果

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTAyODk0_size_16_color_FFFFFF_t_70 2]

当然 处理<!\[CDATA\[\]> 还有其他方式这里的工具类已经集成的处理方式，大家可以根据自己的项目需求进行集成

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTAyODk0_size_16_color_FFFFFF_t_70 1]: /images/20220123/c9270a43e09d442483b333ee533db331.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTAyODk0_size_16_color_FFFFFF_t_70 2]: /images/20220123/e7db300d250946f489fbdd26812f5dfe.png