最近，研究map與java對象之間的相互轉(zhuǎn)換，總結(jié)了5種方法：

第一種：使用org.apache.commons.beanutils轉(zhuǎn)換

用到的主要jar包：commons-beanutils-1.9.3.jar

//map轉(zhuǎn)java對象public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception { if (map == null) { return null; } Object obj = beanClass.newInstance(); BeanUtils.populate(obj, map); return obj; } //java對象轉(zhuǎn)mappublic static Map<?, ?> objectToMap(Object obj) { if (obj == null) return null; return new BeanMap(obj); }

在使用該方法進行java對象轉(zhuǎn)map時，可能會發(fā)生以下錯誤：

Exception in thread 'main' java.lang.NoClassDefFoundError: org/apache/commons/collections/Transformer at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:621) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124) at java.net.URLClassLoader.defineClass(URLClassLoader.java:260) at java.net.URLClassLoader.access$000(URLClassLoader.java:56) at java.net.URLClassLoader$1.run(URLClassLoader.java:195) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) at org.apache.commons.beanutils.BeanMap.createTypeTransformers(BeanMap.java:132) at org.apache.commons.beanutils.BeanMap.<clinit>(BeanMap.java:68) at com.example2.pojo.PojoToMap.objectToMap(PojoToMap.java:23) at com.example2.pojo.PojoToMap.main(PojoToMap.java:16)Caused by: java.lang.ClassNotFoundException: org.apache.commons.collections.Transformer at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) ... 16 more

解決方法見本人的另一篇文章：https://www.jb51.net/article/190471.htm

第二種：使用Introspector轉(zhuǎn)換

//map轉(zhuǎn)java對象public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception { if (map == null) return null; Object obj = beanClass.newInstance(); BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass()); PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors(); for (PropertyDescriptor property : propertyDescriptors) { Method setter = property.getWriteMethod(); if (setter != null) {setter.invoke(obj, map.get(property.getName())); } } return obj; } //java對象轉(zhuǎn)mappublic static Map<String, Object> objectToMap(Object obj) throws Exception { if (obj == null) { return null; } Map<String, Object> map = new HashMap<String, Object>(); BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass()); PropertyDescriptor[] propertyDescriptors = beanInfo .getPropertyDescriptors(); for (PropertyDescriptor property : propertyDescriptors) { String key = property.getName(); if (key.compareToIgnoreCase('class') == 0) { continue; } Method getter = property.getReadMethod(); Object value = getter != null ? getter.invoke(obj) : null; map.put(key, value); } return map;}

第三種：使用reflect轉(zhuǎn)換

//map轉(zhuǎn)java對象public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception { if (map == null) { return null; } Object object = beanClass.newInstance(); Field[] fields = beanClass.getDeclaredFields(); for (Field field : fields) { int mod = field.getModifiers(); if (Modifier.isFinal(mod) || Modifier.isStatic(mod)) {continue; } field.setAccessible(true); field.set(object, map.get(field.getName())); } return object; } //java對象轉(zhuǎn)mappublic static Map<String, Object> objectToMap(Object obj) throws Exception { if (obj == null) { return null; } Map<String, Object> map = new HashMap<String, Object>(); Field[] declaredFields = obj.getClass().getDeclaredFields(); for (Field field : declaredFields) { field.setAccessible(true); map.put(field.getName(), field.get(obj)); } return map;}

第四種：使用net.sf.cglib.beans.BeanMap轉(zhuǎn)換

用到的主要jar包：cglib-2.2.2.jar

//map轉(zhuǎn)java對象public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception { Object object = beanClass.newInstance(); BeanMap beanMap = BeanMap.create(object); beanMap.putAll(map); return object;} //java對象轉(zhuǎn)mappublic static Map<String, Object> objectToMap(Object obj) { Map<String, Object> map = Maps.newHashMap(); if (obj != null) { BeanMap beanMap = BeanMap.create(obj); for (Object key : beanMap.keySet()) { map.put(key + '', beanMap.get(key)); } } return map;}

在使用本方法進行map轉(zhuǎn)java對象時，可能會發(fā)生以下錯誤：

Exception in thread 'main' java.lang.NoClassDefFoundError: org/objectweb/asm/Type at net.sf.cglib.core.TypeUtils.parseType(TypeUtils.java:184) at net.sf.cglib.core.KeyFactory.<clinit>(KeyFactory.java:66) at net.sf.cglib.beans.BeanMap$Generator.<clinit>(BeanMap.java:64) at net.sf.cglib.beans.BeanMap.create(BeanMap.java:56) at com.example2.pojo.MapToPojo.mapToBean(MapToPojo.java:27) at com.example2.pojo.MapToPojo.main(MapToPojo.java:18)Caused by: java.lang.ClassNotFoundException: org.objectweb.asm.Type at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) ... 6 more

解決方法見本人的另一篇文章：https://www.jb51.net/article/190474.htm

第五種：使用json轉(zhuǎn)換

用到的主要jar包：fastjson-1.2.54.jar

//map轉(zhuǎn)java對象public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception { String jsonStr = JSONObject.toJSONString(map); return JSONObject.parseObject(jsonStr, beanClass);} //java對象轉(zhuǎn)mappublic static Map<String, Object> objectToMap(Object obj) { String jsonStr = JSONObject.toJSONString(obj); return JSONObject.parseObject(jsonStr);}

以上方法本人均實際測試通過。到此這篇關(guān)于java中實現(xiàn)map與對象相互轉(zhuǎn)換的幾種實現(xiàn)的文章就介紹到這了,更多相關(guān)java map與對象相互轉(zhuǎn)換內(nèi)容請搜索好吧啦網(wǎng)以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持好吧啦網(wǎng)！