java.lang.reflect.Field的setLong()方法用于将字段的值设置为指定对象上的long。当您需要设置对象字段的值时,可以使用此方法在对象上设置值。
用法:
public void setLong(Object obj, long l) throws IllegalArgumentException, IllegalAccessException
参数:此方法接受接受两个参数:
- obj:是应该修改其字段的对象,并且
- l:这是要修改的obj字段的新值。
返回:此方法不返回任何内容。
异常:此方法引发以下异常:
- IllegalAccessException:如果此Field对象正在强制执行Java语言访问控制,并且基础字段是不可访问的或最终的。
- IllegalArgumentException:如果指定的对象不是声明基础字段(或其子类或实现者)的类或接口的实例,或者展开转换失败。
- NullPolongerException:如果指定的对象为null,并且该字段是实例字段。
- ExceptionInInitializerError:如果此方法引发的初始化失败。
以下示例程序旨在说明setLong()方法:
示例1:
// Java program to illustrate setLong() method
import java.lang.reflect.Field;
public class GFG {
public static void main(String[] args)
throws Exception
{
// create user object
Employee emp = new Employee();
// print value of salary
System.out.prlongln(
"Value of salary before "
+ "applying setLong is "
+ emp.salary);
// Get the field object
Field field = Employee.class.getField("salary");
// Apply setLong Method
field.setLong(emp, 10000000);
// print value of salary
System.out.prlongln(
"Value of salary after "
+ "applying setLong is "
+ emp.salary);
// prlong value of uniqueNo
System.out.prlongln(
"Value of uniqueNo before "
+ "applying setLong is "
+ emp.uniqueNo);
// Get the field object
field = Employee.class.getField("uniqueNo");
// Apply setLong Method
field.setLong(emp, 200000);
// prlong value of uniqueNo
System.out.prlongln(
"Value of uniqueNo after "
+ "applying setLong is "
+ emp.uniqueNo);
}
}
// sample class
class Employee {
// static long values
public static long uniqueNo = 234289;
public static long salary = 1125213;
}
输出:
Value of salary before applying setLong is 1234567 Value of salary after applying setLong is 10000000 Value of uniqueNo before applying setLong is 234289 Value of uniqueNo after applying setLong is 2000000
示例2:
// Java program to illustrate setLong() method
import java.lang.reflect.Field;
public class GFG {
public static void main(String[] args)
throws Exception
{
// create Numbers object
Numbers no = new Numbers();
// Get the value field object
Field field = Numbers.class
.getField("value");
// Apply setLong Method
field.setLong(no, 36283435);
// prlong value of isActive
System.out.prlongln(
"Value after "
+ "applying setLong is "
+ Numbers.value);
}
}
// sample Numbers class
class Numbers {
// static long value
public static long value = 121314454;
}
输出:
Value after applying setLong is 36283435
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注:本文由纯净天空筛选整理自AmanSingh2210大神的英文原创作品 Field setLong() method in Java with Examples。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。