如何通过反射使用一个类的方法

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Java原生态的反射

说明一下 FanSheTime 为我自己随便用的一个类名

用法1：实例化对象，在通过对象直接使用里面的方法即可

public static void main(String[] args) {try {long begin = System.currentTimeMillis();Class<?> forName = Class.forName("lcl.FanSheTime");FanSheTime ss = (FanSheTime) forName.newInstance();ss.function1("hello world");long end = System.currentTimeMillis();System.out.println("耗时>>>>>>>>>>>>>>>>>>>>"+(end - begin));} catch (ClassNotFoundException e) {e.printStackTrace();} catch (SecurityException e) {e.printStackTrace();} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}catch (NoSuchMethodException e) {e.printStackTrace();}catch (IllegalArgumentException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();}}public void function1(String str){System.out.println(str);}public void function1(){System.out.println("hello world");}

方法2：通过反射使用无参数的方法（不实例化对象）

public static void main(String[] args) {try {long begin = System.currentTimeMillis();Class<?> forName = Class.forName("lcl.FanSheTime");Method method = forName.getMethod("function1");method.invoke(forName.newInstance());long end = System.currentTimeMillis();System.out.println("耗时>>>>>>>>>>>>>>>>>>>>"+(end - begin));} catch (ClassNotFoundException e) {e.printStackTrace();} catch (SecurityException e) {e.printStackTrace();} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}catch (NoSuchMethodException e) {e.printStackTrace();}catch (IllegalArgumentException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();}}public void function1(String str){System.out.println(str);}public void function1(){System.out.println("hello world");}

方法3：反射使用带参数的方法：

public static void main(String[] args) {try {long begin = System.currentTimeMillis();Class<?> forName = Class.forName("lcl.FanSheTime");Method method = forName.getMethod("function1",String.class);method.invoke(forName.newInstance(),"焦剑锋");long end = System.currentTimeMillis();System.out.println("耗时>>>>>>>>>>>>>>>>>>>>"+(end - begin));} catch (ClassNotFoundException e) {e.printStackTrace();} catch (SecurityException e) {e.printStackTrace();} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}catch (NoSuchMethodException e) {e.printStackTrace();}catch (IllegalArgumentException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();}}public void function1(String str){System.out.println(str);}public void function1(){System.out.println("hello world");}

如果有多个参数只需要在getMethod方法里面传入不同的参数类型，在invoke方法里传入参数即可

Method method = forName.getMethod("function1",String.class,,String.class,int.class);
method.invoke(forName.newInstance(),"焦剑锋","hello world",1);

方法4：通过bsh-core-2.0b4.jar jar包完成反射

这种方法的好处是，你只需要传入响应的对象与方法名即可通过eval方法进行执行想使用的方法，非常容易

package lcl;import bsh.EvalError;import bsh.Interpreter;public class InterpreterWrapper extends Interpreter {public static void main(String[] args) {FanSheTime fanSheTime = new FanSheTime();InterpreterWrapper ip = new InterpreterWrapper();long begin = System.currentTimeMillis();try {ip.set("fanSheTime", fanSheTime);ip.eval("fanSheTime.function1()");} catch (EvalError e1) {e1.printStackTrace();}long end = System.currentTimeMillis();System.out.println("耗时>>>>>>>>>>>>>>>>>>>>"+(end - begin));}}

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