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常用的map转bean互转方法
- 一、hutool工具类
- 二、fastjson工具类
- 三、beanutils_BeanUtils工具类 不太好用
- 四、cglib BeanMap工具类 不太好用
- 五、reflect 反射来玩 不太好玩
- 六、Introspector类 不太好用
- 总结
一、hutool工具类
这个很常用，还支持将蛇形转成驼，如：apply_time 会赋值到applyTime上
LTDemo ltDemo = BeanUtil.mapToBean(map, LTDemo.class, true, CopyOptions.create());
Map<String, Object> demoMap = BeanUtil.beanToMap(ltDemo);
System.out.println("输出map -> bean: " + ltDemo.toString());
System.out.println("输出bean -> map : " + demoMap);
System.out.println(ltDemo.getApplyTime());
System.out.println(ltDemo.getChildren());
ltDemo.getChildren().forEach(children -> System.out.println(children.toString()));
ltDemo.getChildren().forEach(children -> System.out.println(children.getAddress()));
输出原生map: {address=上海市, children=[{address=上海市, name=小张, apply_time=Fri Mar 03 17:21:01 CST 2023, age=2}], name=张三, apply_time=Fri Mar 03 17:21:01 CST 2023, age=20}
输出map -> bean: LTDemo(name=张三, age=20, address=上海市, applyTime=Fri Mar 03 17:21:01 CST 2023, children=[LTDemo(name=小张, age=2, address=上海市, applyTime=Fri Mar 03 17:21:01 CST 2023, children=[])])
输出bean -> map : {name=张三, age=20, address=上海市, applyTime=Fri Mar 03 17:21:01 CST 2023, children=[LTDemo(name=小张, age=2, address=上海市, applyTime=Fri Mar 03 17:21:01 CST 2023, children=[])]}
Fri Mar 03 17:21:01 CST 2023
[LTDemo(name=小张, age=2, address=上海市, applyTime=Fri Mar 03 17:21:01 CST 2023, children=[])]
LTDemo(name=小张, age=2, address=上海市, applyTime=Fri Mar 03 17:21:01 CST 2023, children=[])
上海市
二、fastjson工具类
这个也很常用，也支持将蛇型转成驼峰，
如：apply_time 会赋值到applyTime上
LTDemo ltDemo = JSONObject.parseObject(JSONObject.toJSONString(map), LTDemo.class);
Map demoMap = JSONObject.parseObject(JSONObject.toJSONString(ltDemo), Map.class);
System.out.println("输出map -> bean: " + ltDemo.toString());
System.out.println("输出bean -> map : " + demoMap);
System.out.println(ltDemo.getApplyTime());
System.out.println(ltDemo.getChildren());
ltDemo.getChildren().forEach(children -> System.out.println(children.toString()));
ltDemo.getChildren().forEach(children -> System.out.println(children.getAddress()));
输出原生map: {address=上海市, children=[{address=上海市, name=小张, apply_time=Fri Mar 03 17:21:59 CST 2023, age=2}], name=张三, apply_time=Fri Mar 03 17:21:59 CST 2023, age=20}
输出map -> bean: LTDemo(name=张三, age=20, address=上海市, applyTime=Fri Mar 03 17:21:59 CST 2023, children=[LTDemo(name=小张, age=2, address=上海市, applyTime=Fri Mar 03 17:21:59 CST 2023, children=[])])
输出bean -> map : {address=上海市, children=[{"address":"上海市","children":[],"name":"小张","applyTime":1677835319813,"age":2}], name=张三, applyTime=1677835319813, age=20}
Fri Mar 03 17:21:59 CST 2023
[LTDemo(name=小张, age=2, address=上海市, applyTime=Fri Mar 03 17:21:59 CST 2023, children=[])]
LTDemo(name=小张, age=2, address=上海市, applyTime=Fri Mar 03 17:21:59 CST 2023, children=[])
上海市
三、beanutils_BeanUtils工具类 不太好用
嵌套型map，转换会有问题，且不支持蛇型转成驼峰
//------------------- beanutils_BeanUtils -----------------
//map转java对象
public static <T> T beanUtils_mapToObject(Map<String, Object> map, Class<T> clazz) throws Exception {
if (map == null) {
return null;
}
T bean = clazz.newInstance();
BeanUtils.populate(bean, map);
return bean;
}
LTDemo ltDemo = beanUtils_mapToObject(map, LTDemo.class);
System.out.println("输出map -> bean: " + ltDemo.toString());
System.out.println(ltDemo.getApplyTime());
System.out.println(ltDemo.getChildren().get(0).getApplyTime());
输出map -> bean: LTDemo(name=张三, age=20, address=上海市, applyTime=Fri Mar 03 17:04:38 CST 2023, children=[{address=上海市, name=小张, applyTime=Fri Mar 03 17:04:38 CST 2023, age=2}])
Fri Mar 03 17:04:38 CST 2023
Exception in thread "main" java.lang.ClassCastException: java.util.HashMap cannot be cast to com.example.demo.map2bean.LTDemo
at com.example.demo.map2bean.MapToBean.main(MapToBean.java:73)
四、cglib BeanMap工具类 不太好用
这个也很常用，也支持将蛇形转成驼，如：apply_time 会赋值到applyTime上
import net.sf.cglib.beans.BeanMap;
// ------------------- cglib BeanMap -------------------
//map对象转java
public static <T> T BeanMapMapToObject(Map<String, Object> map, Class<T> beanClass) throws Exception {
T object = beanClass.newInstance();
BeanMap beanMap = BeanMap.create(object);
beanMap.putAll(map);
return object;
}
//java对象转map
public static Map<String, Object> BeanMapObjectToMap(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;
}
LTDemo ltDemo = beanMapMapToObject(map, LTDemo.class);
Map demoMap = beanMapObjectToMap(ltDemo);
System.out.println("输出map -> bean: " + ltDemo.toString());
System.out.println("输出bean -> map : " + demoMap);
System.out.println(ltDemo.getApplyTime());
System.out.println(ltDemo.getChildren());
ltDemo.getChildren().forEach(children -> System.out.println(children.toString()));
输出原生map: {address=上海市, children=[{address=上海市, name=小张, apply_time=Fri Mar 03 17:12:45 CST 2023, age=2}], name=张三, apply_time=Fri Mar 03 17:12:45 CST 2023, age=20}
输出map -> bean: LTDemo(name=张三, age=20, address=上海市, applyTime=null, children=[{address=上海市, name=小张, apply_time=Fri Mar 03 17:12:45 CST 2023, age=2}])
输出bean -> map : {address=上海市, children=[{address=上海市, name=小张, apply_time=Fri Mar 03 17:12:45 CST 2023, age=2}], name=张三, applyTime=null, age=20}
null
[{address=上海市, name=小张, apply_time=Fri Mar 03 17:12:45 CST 2023, age=2}]
Exception in thread "main" java.lang.ClassCastException: java.util.HashMap cannot be cast to com.example.demo.map2bean.LTDemo
at java.util.ArrayList.forEach(ArrayList.java:1259)
at com.example.demo.map2bean.MapToBean.main(MapToBean.java:75)
五、reflect 反射来玩 不太好玩
//------------------- reflect -------------------
//map转java对象
public static Object reflectMapToObject(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对象转map
public static Map<String, Object> reflectObjectToMap(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;
}
LTDemo ltDemo = reflectMapToObject(map,LTDemo.class);
Map demoMap = reflectObjectToMap(ltDemo);
System.out.println("输出map -> bean: " + ltDemo.toString());
System.out.println("输出bean -> map : " + demoMap);
System.out.println(ltDemo.getApplyTime());
System.out.println(ltDemo.getChildren());
ltDemo.getChildren().forEach(children -> System.out.println(children.toString()));
输出原生map: {address=上海市, children=[{address=上海市, name=小张, apply_time=Fri Mar 03 17:16:35 CST 2023, age=2}], name=张三, apply_time=Fri Mar 03 17:16:35 CST 2023, age=20}
输出map -> bean: LTDemo(name=张三, age=20, address=上海市, applyTime=null, children=[{address=上海市, name=小张, apply_time=Fri Mar 03 17:16:35 CST 2023, age=2}])
输出bean -> map : {address=上海市, children=[{address=上海市, name=小张, apply_time=Fri Mar 03 17:16:35 CST 2023, age=2}], name=张三, applyTime=null, age=20}
null
[{address=上海市, name=小张, apply_time=Fri Mar 03 17:16:35 CST 2023, age=2}]
Exception in thread "main" java.lang.ClassCastException: java.util.HashMap cannot be cast to com.example.demo.map2bean.LTDemo
at java.util.ArrayList.forEach(ArrayList.java:1259)
at com.example.demo.map2bean.MapToBean.main(MapToBean.java:84)
六、Introspector类 不太好用
这个用起来，只能转换第一层，而且不支持蛇型转驼峰
import java.beans.BeanInfo;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
//----------------- Introspector ------------------
//map转java对象
public static <T> T introspector_mapToObject(Map<String, Object> map, Class<T> clazz) throws Exception {
if (map == null) {
return null;
}
T bean = clazz.newInstance();
BeanInfo beanInfo = Introspector.getBeanInfo(bean.getClass());
PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
for (PropertyDescriptor property : propertyDescriptors) {
Method setter = property.getWriteMethod();
if (setter != null) {
setter.invoke(bean, map.get(property.getName()));
}
}
return bean;
}
//java对象转map
public static Map<String, Object> introspector_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;
}
LTDemo ltDemo = introspector_mapToObject(map, LTDemo.class);
Map demoMap = introspector_objectToMap(ltDemo);
System.out.println("输出map -> bean: " + ltDemo.toString());
System.out.println("输出bean -> map : " + demoMap);
System.out.println(ltDemo.getApplyTime());
System.out.println(ltDemo.getChildren());
System.out.println(ltDemo.getChildren().get(0).toString());
输出原生map: {address=上海市, children=[{address=上海市, name=小张, apply_time=Fri Mar 03 16:56:37 CST 2023, age=2}], name=张三, apply_time=Fri Mar 03 16:56:37 CST 2023, age=20}
输出map -> bean: LTDemo(name=张三, age=20, address=上海市, applyTime=null, children=[{address=上海市, name=小张, apply_time=Fri Mar 03 16:56:37 CST 2023, age=2}])
输出bean -> map : {address=上海市, children=[{address=上海市, name=小张, apply_time=Fri Mar 03 16:56:37 CST 2023, age=2}], name=张三, applyTime=null, age=20}
null
[{address=上海市, name=小张, apply_time=Fri Mar 03 16:56:37 CST 2023, age=2}]
Exception in thread "main" java.lang.ClassCastException: java.util.HashMap cannot be cast to com.example.demo.map2bean.LTDemo
at com.example.demo.map2bean.MapToBean.main(MapToBean.java:65)
总结
不想说啥…看着用吧
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