如何在 Java 中使用反射访问私有字段和方法？
如果我们想要使用反射访问私有字段和方法，我们只需要在您想要访问的字段或方法对象上调用 setAccessible(true) 。class . getdeclaredfields(字符串字段名称)或class . getdeclaredfields()可用于获取私有字段。鉴于类. getDeclaredMethod(字符串方法名，类<？> … parameterTypes)或者 Class.getDeclaredMethods()都可以用来获取私有方法。
下面的程序可能无法在在线 IDEs 上运行，比如，只在离线 IDEs 上编译和运行下面的程序。
1。访问私有字段
Java
// Access Private Field Using Reflection in Java
import java.lang.reflect.Field;
// Student class declaration
class Student {
// private fields
private String name;
private int age;
// Constructor
public Student(String name, int age)
{
this.name = name;
this.age = age;
}
// Getters and setters
public String getName() { return name; }
public void setName(String name) { this.name = name; }
private int getAge() { return age; }
public void setAge(int age) { this.age = age; }
// Override toString method to get required
// output at terminal
@Override public String toString()
{
return "Employee [name=" + name + ", age=" + age
+ "]";
}
}
// Program will throw an exception on online IDE
// Compile and run the program on offline IDE
class GFG {
public static void main(String[] args)
{
try {
// Student object created
Student e = new Student("Kapil", 23);
// Create Field object
Field privateField
= Student.class.getDeclaredField("name");
// Set the accessibility as true
privateField.setAccessible(true);
// Store the value of private field in variable
String name = (String)privateField.get(e);
// Print the value
System.out.println("Name of Student:" + name);
}
catch (Exception e) {
e.printStackTrace();
}
}
}
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