【BeanUtils】自己寫的BeanUtils的巢狀使用
阿新 • • 發佈:2019-01-26
其實不打算寫的,因為和前面的是一樣的,不過既然有人問起,我就寫一下吧。
MyBeanUtils
這是核心的類:
通過這個類來返回一個bean物件的。
你給的引數是bean的class和封裝的Map物件。
package cn.hncu.beanUtils;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Map;
/**
* @author 陳浩翔
*
* 2016-8-25
*/
public class MyBeanUtils {
public static<T> T populate(Class<T> cls ,Map<String, Object> map) throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, NoSuchMethodException, SecurityException{
T obj = null;
//1、用類反射new出物件
obj = cls.newInstance();
//2 再用類反射對新new的物件設定屬性值(必須遵守Java設定規範)--即通過setter方法設定
//2.1遍歷出所有該類宣告的屬性
Field flds[] = cls.getDeclaredFields();//getDeclaredFields()返回Class中所有的欄位,包括私有欄位;
for(Field fld:flds){
//獲取該fld物件所代表的屬性名
String fldName = fld.getName();
//根據屬性名,到map中去讀取資料,只有資料非空才需要給該屬性設定值
Object value = map.get(fldName);
if(value==null){//如果map中不存在對應的屬性資料,我們在這裡給出提示資訊
System.out.println(fldName+"的資料為空");
}else{
//如果map中存在對應的屬性資料,則由屬性名得出它的setter方法的名字
String mothodName = "set"+fldName.substring(0, 1).toUpperCase()+fldName.substring(1);
//根據方法名和引數的資料型別(其實就是屬性的型別),獲得Method物件
Class<?> paramTypes[] = new Class[1];
paramTypes[0] = fld.getType();
Method method = cls.getDeclaredMethod(mothodName, paramTypes);
//呼叫該method物件所代表的方法
Object args[] = new Object[1];
args[0]=value;
method.invoke(obj, args);
}
}
return obj;
}
}
Address
package cn.hncu.domain;
/**
* @author 陳浩翔
*
* 2016-8-25
*/
public class Address {
private String province;//省份
private String city;//城市
public Address() {
}
public Address(String province, String city) {
this.province = province;
this.city = city;
}
public String getProvince() {
return province;
}
public void setProvince(String province) {
this.province = province;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
@Override
public String toString() {
return "Address [province=" + province + ", city=" + city + "]";
}
}
Person
package cn.hncu.domain;
import java.util.List;
import java.util.Map;
/**
* @author 陳浩翔
*
* 2016-8-25
*/
public class Person {
private String name;
private int age;
private Address address;
private List lists;
private Map map;
public Person() {
super();
}
public Person(String name, int age, Address address, List lists, Map map) {
super();
this.name = name;
this.age = age;
this.address = address;
this.lists = lists;
this.map = map;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public Address getAddress() {
return address;
}
public void setAddress(Address address) {
this.address = address;
}
public List getLists() {
return lists;
}
public void setLists(List lists) {
this.lists = lists;
}
public Map getMap() {
return map;
}
public void setMap(Map map) {
this.map = map;
}
@Override
public String toString() {
return "Person [name=" + name + ", age=" + age + ", address=" + address
+ ", lists=" + lists + ", map=" + map + "]";
}
}
測試方法:
@Test
@SuppressWarnings({ "rawtypes", "unchecked" })
public void test2() {
Map<String, Object> p = new HashMap();
p.put("name", "Jack");
p.put("age", 100);
p.put("address", new Address("湖南", "長沙"));
List lists = new ArrayList();
lists.add(new Book("B001", "紅樓夢", 25.00, 53.23, 500));
lists.add(new User("U001", "李四", 25));
lists.add("巢狀使用");
p.put("lists", lists);
Map map = new HashMap();
map.put("user", new User("MU002", "MapUser", 30));
map.put("string", "map中的字串");
p.put("map", map);
try {
Person person = MyBeanUtils.populate(Person.class, p);
System.out.println(person);
} catch (ReflectiveOperationException e) {
e.printStackTrace();
}
}
裡面的Book和User類也就是一個bean物件而已。
其實全部可以寫空參構造的,我為了方便,就多寫了有值的構造方法了。
輸出結果:
Person [name=Jack, age=100, address=Address [province=湖南, city=長沙], lists=[Book [uuid=B001, name=紅樓夢, inPrice=25.0, outPrice=53.23, num=500], User [uuid=U001, name=李四, age=25], 巢狀使用], map={string=map中的字串, user=User [uuid=MU002, name=MapUser, age=30]}]
其實和普通的使用沒有什麼不同的。
無非是外面再巢狀一層罷了~