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通过反射获取类的构造方法、字段、方法和注解等信息
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‎README.md‎

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2020

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#Java中级
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##Json
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###Gson
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####代码
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##反射
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* [获取方法、字段和注解](src/cn/aofeng/demo/java/lang/reflect/ClassAnalyze.java)
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##序列化与反序列化
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###Json
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####Gson
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#####代码
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* [普通对象-序列化与反序列化](src/cn/aofeng/demo/json/gson/SimpleObjectSerialize.java)
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* [数组-序列化](src/cn/aofeng/demo/json/gson/ArraySerialize.java)
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* [数组-反序列化](src/cn/aofeng/demo/json/gson/ArrayDeserialize.java)
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* [自定义序列化](src/cn/aofeng/demo/json/gson/CustomSerialize.java)
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* [自定义反序列化](src/cn/aofeng/demo/json/gson/CustomDeserialize.java)
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####文章
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#####文章
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* [Gson教程-序列化与反序列化基础操作](http://aofengblog.blog.163.com/blog/static/6317021201571275718825/)
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##定时器

‎src/cn/aofeng/demo/java/lang/reflect/ClassAnalyze.java‎

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package cn.aofeng.demo.java.lang.reflect;
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import java.lang.annotation.Annotation;
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import java.lang.reflect.AnnotatedElement;
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import java.lang.reflect.Constructor;
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import java.lang.reflect.Field;
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import java.lang.reflect.Method;
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import java.lang.reflect.Modifier;
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/**
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* 通过反射获取类的构造方法、字段、方法和注解等信息。
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*
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* @author <a href="mailto:[email protected]">聂勇</a>
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*/
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public class ClassAnalyze {
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final static String PREFIX = "==========";
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final static String SUFFIX = PREFIX;
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private static void parseClass(Class<?> claz) {
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// 注解
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parseAnnotation(claz);
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// 类
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StringBuilder buffer = new StringBuilder(32)
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.append( Modifier.toString(claz.getModifiers()) )
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.append(' ')
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.append(claz.getName());
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log(buffer.toString());
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}
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private static void parseConstructor(Constructor<?> c) {
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// 注解
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parseAnnotation(c);
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// 构造方法
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StringBuilder buffer = new StringBuilder(32)
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.append( Modifier.toString(c.getModifiers()) )
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.append(' ')
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.append(c.getName())
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.append('(');
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// 参数
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Class<?>[] params = c.getParameterTypes();
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for (int index = 0; index < params.length; index++) {
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buffer.append(params[index].getName());
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if (index!=params.length-1) {
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buffer.append(", ");
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}
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}
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buffer.append(')');
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log(buffer.toString());
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}
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private static void parseMethod(Method method) {
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// 注解
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parseAnnotation(method);
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// 方法
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StringBuilder buffer = new StringBuilder(32)
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.append( Modifier.toString(method.getModifiers()) )
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.append(' ')
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.append(method.getName())
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.append('(');
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// 参数
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Class<?>[] params = method.getParameterTypes();
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for (int index = 0; index < params.length; index++) {
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buffer.append(params[index].getName());
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if (index!=params.length-1) {
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buffer.append(", ");
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}
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}
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buffer.append(')');
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log(buffer.toString());
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}
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private static void parseField(Field field) {
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// 注解
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parseAnnotation(field);
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// 字段
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StringBuilder buffer = new StringBuilder()
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.append(Modifier.toString(field.getModifiers()))
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.append(' ')
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.append(field.getName());
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log(buffer.toString());
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}
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/**
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* 解析注解信息。
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*/
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private static void parseAnnotation(AnnotatedElement ae) {
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Annotation[] ans = ae.getDeclaredAnnotations();
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for (Annotation annotation : ans) {
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log(annotation.toString());
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}
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}
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public static void log(String msg, Object... param) {
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System.out.println( String.format(msg, param) );
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}
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public static void main(String[] args) throws ClassNotFoundException {
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if (args.length != 1) {
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log("无效的输入参数！");
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log("示例：");
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log("java cn.aofeng.demo.java.lang.reflect.ClassAnalyze java.util.HashMap");
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}
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Class<?> claz = Class.forName(args[0]);
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log("%s类%s", PREFIX, SUFFIX);
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parseClass(claz);
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log("%s构造方法%s", PREFIX, SUFFIX);
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Constructor<?>[] cs = claz.getDeclaredConstructors();
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for (Constructor<?> constructor : cs) {
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parseConstructor(constructor);
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}
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log("%s字段%s", PREFIX, SUFFIX);
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Field[] fields = claz.getDeclaredFields();
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for (Field field : fields) {
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parseField(field);
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}
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log("%s方法%s", PREFIX, SUFFIX);
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Method[] methods = claz.getDeclaredMethods();
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for (Method method : methods) {
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parseMethod(method);
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}
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}
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}

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