自定义test之java json字符串转为java对象

最近作者在上一篇java json字符串转map或list（http://blog.csdn.net/zqy1992/article/details/70189997）的基础上实现了把json字符串转为普通java对象的简单功能，还望大家批评指正。

private static <T> T parseObject(String input,Class<T> clazz) throws Exception{

if(input == null){

return null;

}

Map<String,Object> map = (Map<String, Object>) JsonPrase2Test.getObject(input);

return parseObjectImpl(map,clazz);

}

private static <T> T parseObjectImpl(Map<String,Object> map,Class<T> clazz) throws Exception{

if(map == null || map.size() <= 0){

return null;

}

Field[] fields = clazz.getDeclaredFields();

T t = (T) Class.forName(clazz.getName()).newInstance();

for(Field field : fields){

try{

PropertyDescriptor propertyDescriptor = new PropertyDescriptor(field.getName(), clazz);

Method setMechod = propertyDescriptor.getWriteMethod();

if(handlePrimitiveClass(field.getType(),setMechod,t,map.get(field.getName()))){

}else if(field.getType().isAssignableFrom(List.class)){

List objectlist = new ArrayList();

List valueList = (List) map.get(field.getName());

Type type = field.getGenericType();//得到其generic类型

if(type instanceof ParameterizedType){//如果是泛型

ParameterizedType parameterizedType = (ParameterizedType) type;//暂时只处理泛型是普通objectl类型（不处理泛型是list类型）

Class genericClass = (Class) parameterizedType.getActualTypeArguments()[0];

for(Object value:valueList){

objectlist.add(parseObjectImpl((Map<String, Object>) value, genericClass));

}else{

objectlist = valueList ;

}

setMechod.invoke(t,objectlist);

}

}else{//普通对象Object

setMechod.invoke(t,parseObjectImpl((Map<String, Object>) map.get(field.getName()),field.getType()));

}

}catch (Exception e){

System.out.println("处理属性"+ field.getName()+" 异常！ exception="+e.getClass());

}

}

return t;

}

private static boolean handlePrimitiveClass(Class clazz,Method setMethod,Object obj,Object value) throws Exception {

try {

if(value == null){

 return true;

}

String str = value.toString();

if (clazz.isAssignableFrom(Integer.class) || clazz.isAssignableFrom(int.class)) {

setMethod.invoke(obj, Integer.valueOf(str));

} else if (clazz.isAssignableFrom(Double.class) || clazz.isAssignableFrom(double.class)) {

setMethod.invoke(obj, Double.valueOf(str));

} else if (clazz.isAssignableFrom(Float.class) || clazz.isAssignableFrom(Float.class)) {

setMethod.invoke(obj, Float.valueOf(str));

} else if (clazz.isAssignableFrom(Long.class) || clazz.isAssignableFrom(Long.class)) {

setMethod.invoke(obj, Long.valueOf(str));

} else if (clazz.isAssignableFrom(Short.class) || clazz.isAssignableFrom(Short.class)) {

setMethod.invoke(obj,Short.valueOf(str));

} else if (clazz.isAssignableFrom(Character.class) || clazz.isAssignableFrom(Character.class)) {

setMethod.invoke(obj,str);

} else if (clazz.isAssignableFrom(String.class) || clazz.isAssignableFrom(String.class)) {

setMethod.invoke(obj, str);

}else if (clazz.isAssignableFrom(Map.class)) {

setMethod.invoke(obj, value);

}else {

return false;

}

return true;

}catch (Exception e){

throw new Exception();

}

}

代码首先把json格式的字符串（这里默认是普通对象类型）转为map，根据反射获取要转为java对象的属性列表，根据属性名字在map查找然后把结果直接赋值。