class="markdown_views prism-atom-one-dark">

class="tags" href="/tags/FanShe.html" title=反射>反射（英语：reflection）是指计算机程序在运行时（runtime）可以访问、检测和修改它本身状态或行为的一种能力。用比喻来说，class="tags" href="/tags/FanShe.html" title=反射>反射就是程序在运行的时候能够“观察”并且修改自己的行为。
1.class="tags" href="/tags/FanShe.html" title=反射>反射类
举个例子：

class="prism language-class="tags" href="/tags/JAVA.html" title=java>javascript">class="token keyword">public class="token keyword">class class="token class-name">Foo class="token punctuation">{
	
	class="token keyword">public class="token keyword">void class="token function">helloclass="token punctuation">(class="token punctuation">) class="token punctuation">{
		Systemclass="token punctuation">.outclass="token punctuation">.class="token function">printlnclass="token punctuation">(class="token string">"hello"class="token punctuation">)class="token punctuation">;
	class="token punctuation">}

	class="token keyword">public class="token keyword">static class="token keyword">void class="token function">mainclass="token punctuation">(Stringclass="token punctuation">[class="token punctuation">] argsclass="token punctuation">) class="token punctuation">{
		class="token keyword">try class="token punctuation">{
		    Object foo class="token operator">= Classclass="token punctuation">.class="token function">forNameclass="token punctuation">(class="token string">"complete.classpath.and.Foo"class="token punctuation">)class="token punctuation">.class="token function">newInstanceclass="token punctuation">(class="token punctuation">)class="token punctuation">;
		    Method m class="token operator">= fooclass="token punctuation">.class="token function">getClassclass="token punctuation">(class="token punctuation">)class="token punctuation">.class="token function">getDeclaredMethodclass="token punctuation">(class="token string">"hello"class="token punctuation">, class="token keyword">new class="token class-name">Classclass="token operator"><class="token operator">?class="token operator">>class="token punctuation">[class="token number">0class="token punctuation">]class="token punctuation">)class="token punctuation">;
		    mclass="token punctuation">.class="token function">invokeclass="token punctuation">(fooclass="token punctuation">)class="token punctuation">;
		class="token punctuation">} class="token keyword">catch class="token punctuation">(class="token class-name">Exception eclass="token punctuation">) class="token punctuation">{
		    class="token comment">// Catching ClassNotFoundException, NoSuchMethodException
		    class="token comment">// InstantiationException, IllegalAccessException
		class="token punctuation">}

	class="token punctuation">}

class="token punctuation">}

2.class="tags" href="/tags/FanShe.html" title=反射>反射构造函数
举个例子：

class="prism language-class="tags" href="/tags/JAVA.html" title=java>javascript">class="token keyword">public class="token keyword">class class="token class-name">Foo class="token punctuation">{
	class="token keyword">public class="token function">Fooclass="token punctuation">(String sclass="token punctuation">, String aclass="token punctuation">) class="token punctuation">{
		
	class="token punctuation">}
	
	class="token keyword">public class="token keyword">void class="token function">helloclass="token punctuation">(class="token punctuation">) class="token punctuation">{
		Systemclass="token punctuation">.outclass="token punctuation">.class="token function">printlnclass="token punctuation">(class="token string">"hello"class="token punctuation">)class="token punctuation">;
	class="token punctuation">}	
	class="token keyword">public class="token keyword">static class="token keyword">void class="token function">mainclass="token punctuation">(Stringclass="token punctuation">[class="token punctuation">] argsclass="token punctuation">) class="token punctuation">{
		class="token keyword">try class="token punctuation">{
			Classclass="token operator"><class="token operator">?class="token operator">> classFoo class="token operator">= Classclass="token punctuation">.class="token function">forNameclass="token punctuation">(class="token string">"complete.classpath.and.Foo"class="token punctuation">)class="token punctuation">;
			Constructorclass="token operator"><class="token operator">?class="token operator">> declaredConstructorFoo class="token operator">= classFooclass="token punctuation">.class="token function">getDeclaredConstructorclass="token punctuation">(Stringclass="token punctuation">.class="token keyword">classclass="token punctuation">, Stringclass="token punctuation">.class="token keyword">classclass="token punctuation">)class="token punctuation">;
			declaredConstructorFooclass="token punctuation">.class="token function">setAccessibleclass="token punctuation">(class="token boolean">trueclass="token punctuation">)class="token punctuation">;
			Object foo class="token operator">= declaredConstructorFooclass="token punctuation">.class="token function">newInstanceclass="token punctuation">(class="token string">"a"class="token punctuation">, class="token string">"b"class="token punctuation">)class="token punctuation">;
		    Method m class="token operator">= fooclass="token punctuation">.class="token function">getClassclass="token punctuation">(class="token punctuation">)class="token punctuation">.class="token function">getDeclaredMethodclass="token punctuation">(class="token string">"hello"class="token punctuation">, class="token keyword">new class="token class-name">Classclass="token operator"><class="token operator">?class="token operator">>class="token punctuation">[class="token number">0class="token punctuation">]class="token punctuation">)class="token punctuation">;
		    mclass="token punctuation">.class="token function">invokeclass="token punctuation">(fooclass="token punctuation">)class="token punctuation">;
		class="token punctuation">} class="token keyword">catch class="token punctuation">(class="token class-name">Exception eclass="token punctuation">) class="token punctuation">{
			class="token comment">// Catching ClassNotFoundException, NoSuchMethodException
			class="token comment">// InstantiationException, IllegalAccessException
		class="token punctuation">}

	class="token punctuation">}

class="token punctuation">}

3.class="tags" href="/tags/FanShe.html" title=反射>反射成员变量
举个例子：

class="prism language-class="tags" href="/tags/JAVA.html" title=java>javascript">class="token keyword">public class="token keyword">class class="token class-name">Foo class="token punctuation">{

class="token keyword">public String ttt class="token operator">= class="token string">"aaaaaa"class="token punctuation">;
	class="token keyword">public class="token function">Fooclass="token punctuation">(String sclass="token punctuation">, String aclass="token punctuation">) class="token punctuation">{
		
	class="token punctuation">}
	
	class="token keyword">public class="token keyword">void class="token function">helloclass="token punctuation">(class="token punctuation">) class="token punctuation">{
		Systemclass="token punctuation">.outclass="token punctuation">.class="token function">printlnclass="token punctuation">(class="token string">"hello"class="token punctuation">)class="token punctuation">;
	class="token punctuation">}	
	class="token keyword">public class="token keyword">static class="token keyword">void class="token function">mainclass="token punctuation">(Stringclass="token punctuation">[class="token punctuation">] argsclass="token punctuation">) class="token punctuation">{
		class="token keyword">try class="token punctuation">{
         Classclass="token operator"><class="token operator">?class="token operator">> classFoo class="token operator">= Classclass="token punctuation">.class="token function">forNameclass="token punctuation">(class="token string">"complete.classpath.and.Foo"class="token punctuation">)class="token punctuation">;
            Object foo class="token operator">= classFooclass="token punctuation">.class="token function">newInstanceclass="token punctuation">(class="token punctuation">)class="token punctuation">;
            Field fieldttt class="token operator">= classFooclass="token punctuation">.class="token function">getDeclaredFieldclass="token punctuation">(class="token string">"ttt"class="token punctuation">)class="token punctuation">;
            fieldtttclass="token punctuation">.class="token function">setAccessibleclass="token punctuation">(class="token boolean">trueclass="token punctuation">)class="token punctuation">;
            String ttt class="token operator">= class="token punctuation">(Stringclass="token punctuation">) fieldtttclass="token punctuation">.class="token keyword">getclass="token punctuation">(classFooclass="token punctuation">)class="token punctuation">;
            Systemclass="token punctuation">.outclass="token punctuation">.class="token function">printlnclass="token punctuation">(class="token string">"reflectPrivateField tag = " class="token operator">+ tttclass="token punctuation">)class="token punctuation">;		class="token punctuation">} class="token keyword">catch class="token punctuation">(class="token class-name">Exception eclass="token punctuation">) class="token punctuation">{
			class="token comment">// Catching ClassNotFoundException, NoSuchMethodException
			class="token comment">// InstantiationException, IllegalAccessException
		class="token punctuation">}

	class="token punctuation">}

class="token punctuation">}

4.class="tags" href="/tags/FanShe.html" title=反射>反射私有方法
举个例子：

class="prism language-class="tags" href="/tags/JAVA.html" title=java>javascript">class="token keyword">public class="token keyword">class class="token class-name">Foo class="token punctuation">{
	class="token keyword">public class="token function">Fooclass="token punctuation">(String sclass="token punctuation">, String aclass="token punctuation">) class="token punctuation">{
		
	class="token punctuation">}
	
	class="token keyword">public class="token keyword">void class="token function">helloclass="token punctuation">(class="token punctuation">) class="token punctuation">{
		Systemclass="token punctuation">.outclass="token punctuation">.class="token function">printlnclass="token punctuation">(class="token string">"hello"class="token punctuation">)class="token punctuation">;
	class="token punctuation">}	

	class="token keyword">private class="token keyword">void class="token function">sssclass="token punctuation">(class="token punctuation">) class="token punctuation">{
		Systemclass="token punctuation">.outclass="token punctuation">.class="token function">printlnclass="token punctuation">(class="token string">"sss"class="token punctuation">)class="token punctuation">;
	class="token punctuation">}
	class="token keyword">public class="token keyword">static class="token keyword">void class="token function">mainclass="token punctuation">(Stringclass="token punctuation">[class="token punctuation">] argsclass="token punctuation">) class="token punctuation">{
		class="token keyword">try class="token punctuation">{
		    Object foo class="token operator">= Classclass="token punctuation">.class="token function">forNameclass="token punctuation">(class="token string">"complete.classpath.and.Foo"class="token punctuation">)class="token punctuation">.class="token function">newInstanceclass="token punctuation">(class="token punctuation">)class="token punctuation">;
		    Method m class="token operator">= fooclass="token punctuation">.class="token function">getClassclass="token punctuation">(class="token punctuation">)class="token punctuation">.class="token function">getDeclaredMethodclass="token punctuation">(class="token string">"sss"class="token punctuation">, class="token keyword">new class="token class-name">Classclass="token operator"><class="token operator">?class="token operator">>class="token punctuation">[class="token number">0class="token punctuation">]class="token punctuation">)class="token punctuation">;
		    mclass="token punctuation">.class="token function">setAccessibleclass="token punctuation">(class="token boolean">trueclass="token punctuation">)class="token punctuation">;
		    mclass="token punctuation">.class="token function">invokeclass="token punctuation">(fooclass="token punctuation">)class="token punctuation">;		class="token punctuation">} class="token keyword">catch class="token punctuation">(class="token class-name">Exception eclass="token punctuation">) class="token punctuation">{
			class="token comment">// Catching ClassNotFoundException, NoSuchMethodException
			class="token comment">// InstantiationException, IllegalAccessException
		class="token punctuation">}

	class="token punctuation">}

class="token punctuation">}

以上就是class="tags" href="/tags/JAVA.html" title=java>java中class="tags" href="/tags/FanShe.html" title=反射>反射的一些用法。