BeanUtils beanjavaBean与Map互转
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 |
Java代码 import java.lang.reflect.InvocationTargetException; import java.util.Map; import org.apache.commons.beanutils.BeanUtils; public class test { public static void main(String[] args) { Person person1=new Person(); person1.setName("name1"); person1.setSex("sex1"); Map<String, String> map=null; try { map = BeanUtils.describe(person1); //=============Bean转换成Map=======================// System.out.println(map.size()+">>>>>>>>>>>"); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } catch (NoSuchMethodException e) { // TODO Auto-generated catch block e.printStackTrace(); } Person person=test.map2Bean(map, Person.class); System.out.println(person.getName()); } /** * * * Map转换层Bean，使用泛型免去了类型转换的麻烦。 * @param <T> * @param map * @param class1 * @return */ public static <T> T map2Bean(Map<String, String> map, Class<T> class1) { T bean = null; try { bean = class1.newInstance(); BeanUtils.populate(bean, map); } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } return bean; } } |
其他例子
http://stackoverflow.com/questions/21720128/beanutils-converting-java-util-map-to-nested-bean
Map转换到Bean
BeanOne.java
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 |
Java代码 import java.util.Map; public class BeanOne { private String fieldOne; private Map<String,BeanTwo> fieldTwo; public Map<String, BeanTwo> getFieldTwo() { return fieldTwo; } public void setFieldTwo(Map<String, BeanTwo> fieldTwo) { this.fieldTwo = fieldTwo; } public String getFieldOne() { return this.fieldOne; } public void setFieldOne(String fieldOne) { this.fieldOne = fieldOne; } } |
BeanTwo.java
|
1 2 3 4 5 6 7 8 9 10 11 12 |
Java代码 public class BeanTwo { private String fieldOne; public String getFieldOne() { return this.fieldOne; } public void setFieldOne(String fieldOne) { this.fieldOne = fieldOne; } } |
Tester.java
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 |
Java代码 import java.lang.reflect.InvocationTargetException; import java.util.HashMap; import java.util.Map; import org.apache.commons.beanutils.BeanUtils; public class Tester { public static void main(String[] args) throws IllegalAccessException, InvocationTargetException { Map beanTwoMap = new HashMap(); beanTwoMap.put("fieldOne", "fieldOne2222Value"); Map beanOneMap = new HashMap(); beanOneMap.put("fieldOne", "fieldOneValue"); beanOneMap.put("fieldTwo", beanTwoMap); BeanOne beanOne = new BeanOne(); BeanUtils.populate(beanOne, beanOneMap); System.out.println(beanOne.getFieldOne()); System.out.println(beanOne.getFieldTwo().get("fieldOne")); } } |
output will be:-
fieldOneValue
fieldOne2222Value
javaBean与Map<String,Object>互转
方法1： 利用java.beans.Introspector和java.beans.PropertyDescriptor实现 javaBean与Map<String,Object>互转
方法2： 利用org.apache.commons.beanutils.BeanUtils工具类，BeanUtils.populate实现Map 转换为javaBean
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 |
Java代码 package javaStudyDemo.bean.reflect.test; import java.beans.BeanInfo; import java.beans.Introspector; import java.beans.PropertyDescriptor; import java.lang.reflect.Method; import java.util.HashMap; import java.util.Map; import javaStudyDemo.others.PersonBean; import org.apache.commons.beanutils.BeanUtils; /** * 当把Person类作为BeanUtilTest的内部类时，程序出错<br> * java.lang.NoSuchMethodException: Property '**' has no setter method<br> * 本质：内部类 和 单独文件中的类的区别 <br> * BeanUtils.populate方法的限制：<br> * The class must be public, and provide a public constructor that accepts no arguments. <br> * This allows tools and applications to dynamically create new instances of your bean, <br> * without necessarily knowing what Java class name will be used ahead of time */ public class BeanUtilTest { public static void main(String[] args) { PersonBean person = new PersonBean(); Map<String, Object> mp = new HashMap<String, Object>(); mp.put("name", "Mike"); mp.put("age", 25); mp.put("mN", "male"); // 将map转换为bean transMap2Bean2(mp, person); System.out.println("--- transMap2Bean Map Info: "); for (Map.Entry<String, Object> entry : mp.entrySet()) { System.out.println(entry.getKey() + ": " + entry.getValue()); } System.out.println("--- Bean Info: "); System.out.println("name: " + person.getName()); System.out.println("age: " + person.getAge()); System.out.println("mN: " + person.getmN()); // 将javaBean 转换为map Map<String, Object> map = transBean2Map(person); System.out.println("--- transBean2Map Map Info: "); for (Map.Entry<String, Object> entry : map.entrySet()) { System.out.println(entry.getKey() + ": " + entry.getValue()); } } // Map --> Bean 2: 利用org.apache.commons.beanutils 工具类实现 Map --> Bean public static void transMap2Bean2(Map<String, Object> map, Object obj) { if (map == null || obj == null) { return; } try { BeanUtils.populate(obj, map); } catch (Exception e) { System.out.println("transMap2Bean2 Error " + e); } } // Map --> Bean 1: 利用Introspector,PropertyDescriptor实现 Map --> Bean public static void transMap2Bean(Map<String, Object> map, Object obj) { try { BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass()); PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors(); for (PropertyDescriptor property : propertyDescriptors) { String key = property.getName(); if (map.containsKey(key)) { Object value = map.get(key); // 得到property对应的setter方法 Method setter = property.getWriteMethod(); setter.invoke(obj, value); } } } catch (Exception e) { System.out.println("transMap2Bean Error " + e); } return; } // Bean --> Map 1: 利用Introspector和PropertyDescriptor 将Bean --> Map public static Map<String, Object> transBean2Map(Object obj) { if(obj == null){ return null; } Map<String, Object> map = new HashMap<String, Object>(); try { BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass()); PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors(); for (PropertyDescriptor property : propertyDescriptors) { String key = property.getName(); // 过滤class属性 if (!key.equals("class")) { // 得到property对应的getter方法 Method getter = property.getReadMethod(); Object value = getter.invoke(obj); map.put(key, value); } } } catch (Exception e) { System.out.println("transBean2Map Error " + e); } return map; } } |
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 |
Java代码 public class PersonBean { private String name; private Integer age; private String mN; /** * @return the mN */ public String getmN() { return mN; } /** * @param mN the mN to set */ public void setmN(String mN) { this.mN = mN; } /** * @return the name */ public String getName() { return name; } /** * @param name the name to set */ public void setName(String name) { this.name = name; } /** * @return the age */ public Integer getAge() { return age; } /** * @param age the age to set */ public void setAge(Integer age) { this.age = age; } } |
总结： javaBean与Map<String,Object>互转利用到了java的内省（ Introspector ）和反射（reflect）机制。 其思路为： 通过类 Introspector 来获取某个对象的 BeanInfo 信息，然后通过 BeanInfo 来获取属性的描述器PropertyDescriptor，再利用属性描述器获取某个属性对应的 getter/setter 方法，然后通过反射机制来getter和setter。
