复用代码系列：Spring的BeanUtils操作

偏执的太偏执、 2022-05-26 13:37 194阅读 0赞

package com.spring.tools;
    
    import java.beans.PropertyDescriptor;
    import java.lang.reflect.Method;
    
    import org.junit.Test;
    import org.springframework.beans.BeanInstantiationException;
    import org.springframework.beans.BeanUtils;
    
    public class BeanUtilsTest {
    	/**
    	 * 实例化
    	 */
    	@Test
    	public void testInstantiate() {
    		//通过无参数构造函数实例化
    		Object obj = BeanUtils.instantiate(Person.class);
    		//Object obj = BeanUtils.instantiateClass(Person.class); //与BeanUtils.instantiate(Person.class)一样
    		if(obj instanceof Person) {
    			System.out.println(((Person) obj).getName());
    		}
    		
    		//通过有参数构造函数实例化
    		Object obj2;
    		try {
    			obj2 = BeanUtils.instantiateClass(Person.class.getDeclaredConstructor(String.class), "a");
    			if(obj2 instanceof Person) {
    				System.out.println(((Person) obj2).getName());
    			}
    		} catch (BeanInstantiationException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (NoSuchMethodException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (SecurityException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		
    	}
    	
    	/**
    	 * 查找方法
    	 * @throws Exception
    	 */
    	@Test
    	public void testFindDeclaredMethod() throws Exception {
    		User user = new User();
    		user.setCode("1");
    		user.setName("suncht");
    		
    		//在所有方法中查找
    		Method method1 = BeanUtils.findDeclaredMethod(User.class, "getCode");
    		Object code1 = method1.invoke(user);
    		System.out.println(code1);
    		
    		//在公共方法中查找
    		Method method2 = BeanUtils.findMethod(User.class, "getName");
    		Object code2 = method2.invoke(user);
    		System.out.println(code2);
    		
    	}
    	
    	/**
    	 * 查找属性
    	 * @throws Exception
    	 */
    	@Test
    	public void testPropertyDescriptor() throws Exception {
    		User user = new User();
    		user.setCode("222");
    		user.setName("suncht");
    		
    		//获取属性
    		PropertyDescriptor pd = BeanUtils.getPropertyDescriptor(User.class, "code");
    		
    		//获取属性的get方法
    		Method getMethod = pd.getReadMethod();
    		Object code1 = getMethod.invoke(user);
    		System.out.println(code1);
    		
    		//获取属性的get方法
    		Method setMethod = pd.getWriteMethod();
    		setMethod.invoke(user, "333");
    		System.out.println(user.getCode());
    		
    		//根据方法查找属性
    		Method getCodeMethod = BeanUtils.findDeclaredMethod(User.class, "getCode2");
    		PropertyDescriptor pd2 = BeanUtils.findPropertyForMethod(getCodeMethod);
    		System.out.println(pd2);
    	}
    	
    	
    	public static class Person {
    		private String name = "aa";
    		
    		public Person() {
    			
    		}
    		
    		public Person(String name) {
    			this.name = name;
    		}
    
    		public String getName() {
    			return name;
    		}
    
    		public void setName(String name) {
    			this.name = name;
    		}
    	}
    	
    	public static class User extends Person {
    		private String code;
    
    		public String getCode() {
    			return code;
    		}
    
    		public void setCode(String code) {
    			this.code = code;
    		}
    		
    		private String getCode2() {
    			return code;
    		}
    		
    	}
    }