反射获取java对象的几种方式

Class clazz = Class.forName("java.util.ArrayList");

Class clazz = String.class;

String str = "Hello";
Class clazz = str.getClass();

//1.创建对象
Class clazz = MyClass.class;  // 假设 MyClass 是一个类
MyClass obj = (MyClass) clazz.newInstance();  // 创建 MyClass 的实例

//2.调用成员变量
Class clazz = MyClass.class;
Field field = clazz.getDeclaredField("fieldName");  // 获取字段对象
field.setAccessible(true);  // 设置可访问私有字段
Object value = field.get(obj);  // 获取字段值
field.set(obj, newValue);  // 设置字段值
// 获取字段值
Object value = field.get(obj);
System.out.println("原始值：" + value);
// 修改字段值
field.set(obj, newValue);
System.out.println("修改后：" + field.get(obj));

//3.调用方法
Class clazz = MyClass.class;
Method method = clazz.getDeclaredMethod("methodName", argTypes);  // 获取方法对象
method.setAccessible(true);  // 设置可访问私有方法
Object result = method.invoke(obj, args);  // 调用方法并获取返回值

Class clazz = MyClass.class;

// 获取无参构造函数，创建实例
MyClass obj1 = (MyClass) clazz.newInstance();

// 获取有参构造函数，创建实例
Constructor constructor = clazz.getDeclaredConstructor(String.class, int.class);
MyClass obj2 = (MyClass) constructor.newInstance("name", 18);

package com.xiaojiang.Spring;
 
public class Role {
     
    private int id;
    private String roleName;
    private String note;
     
    public Role(){}
     
    public Role(int id,String roleName, String note)
    {　　　　　　　　　 
    	super();
        this.id = id;
        this.roleName = roleName;
        this.note = note;
    }　　　　　//setter,getter方法省略
 
}

<!--构造器配置-->
<bean id="Role" class="com.xiaojiang.Spring.Role">
        <constructor-arg value="1" type="int"></constructor-arg>
        <constructor-arg value="小江" type="java.lang.String"></constructor-arg>
        <constructor-arg value="有点丑" type="java.lang.String"></constructor-arg>
    </bean>

<!--配置setter注入-->
<bean id="Role" class="com.xiaojiang.Spring.Role">
        <property name="id" value="1"><property>
        <property name="roleName" value="小江"><property>
        <property name="note" value="测试"><property>
</bean>