JAVA反射機制：是在運行狀態中，能夠獲得這個類的所有屬性和方法，都能夠調用它的任意一個方法和屬性，這種動態獲取類的信息以及動態調用對象的方法的功能稱為反射機制。

下面將通過反射獲取類的信息

person類

public class PersonBean {    PRivate String Name;    private int age;    private double price;    private boolean isMarry;    protected String mobile;    public String address;    public void setIsMarry(boolean isMarry) {        this.isMarry = isMarry;    }    public boolean isMarry() {        return isMarry;    }    public void setAddress(String address) {        this.address = address;    }    public void setAge(int age) {        this.age = age;    }    public void setMobile(String mobile) {        this.mobile = mobile;    }    public void setName(String name) {        Name = name;    }    public void setPrice(double price) {        this.price = price;    }    public String getAddress() {        return address;    }    public int getAge() {        return age;    }    public String getMobile() {        return mobile;    }    public String getName() {        return Name;    }    public double getPrice() {        return price;    }}

反射獲取相關代碼：

public class Test {    public static void main(String[] args) {        System.out.println();        System.out.println("setField:");        setField();        System.out.println();        System.out.println("getFields:");        getFields();        System.out.println();        System.out.println("invokeMethod:");        invokeMethod();        System.out.println();        System.out.println("getMethod:");        getMethod();    }    /**     * 調用方法     */    private static void invokeMethod() {        Class clazz = getClass(PersonBean.class.getName());        try {            Object object = clazz.newInstance();            System.out.println("age is :"+ (((PersonBean)object).getAge()));            Method method = clazz.getMethod("setAge", int.class);            method.invoke(object, 123456);            Method method1 = clazz.getMethod("getAge");            int age = (int) method1.invoke(object);            System.out.println("age is :"+ age);        } catch (Exception e) {            e.printStackTrace();        }    }    /**     * 設置屬性     */    private static void setField() {        Class clazz = getClass(PersonBean.class.getName());        try {            PersonBean personBean = (PersonBean) clazz.newInstance();            Field[] fields = clazz.getDeclaredFields();            System.out.println("設置屬性：");            for (int i = 0; i < fields.length; i++) {                Field field = fields[i];                field.setaccessible(true);                if (field.getType().equals(int.class)) {                    field.setInt(personBean, 24);                } else if (field.getType().equals(double.class)) {                    field.setDouble(personBean, 24);                } else if (field.getType().equals(float.class)) {                } else if (field.getType().equals(boolean.class)) {                    field.setBoolean(personBean, true);                } else if (field.getType().equals(String.class)) {                    field.set(personBean, "廣州");                }            }            System.out.println(personBean.getAge());            System.out.println(personBean.getAddress());        } catch (InstantiationException e) {            e.printStackTrace();        } catch (IllegalAccessException e) {            e.printStackTrace();        }    }    /**     * 獲取所有屬性     */    private static void getFields() {        Class clazz = getClass(PersonBean.class.getName());        Field[] fields = clazz.getDeclaredFields();        System.out.println("屬性有：");        for (int i = 0; i < fields.length; i++) {            System.out.println(Modifier.toString(fields[i].getModifiers())+" "+fields[i].getType().getSimpleName()+" "+fields[i].getName());        }    }    private static String getModifiers(int modifiers) {        String modifierName;        Modifier modifier = new Modifier();        if (modifier.isPublic(modifiers)) {            modifierName = "public";        } else if (modifier.isProtected(modifiers)) {            modifierName = "protected";        } else if (modifier.isPrivate(modifiers)) {            modifierName = "private";        } else {            modifierName = modifiers+"";        }        return modifierName;    }    /**     * 獲取所有方法     */    private static void getMethod() {        Class clazz = getClass(PersonBean.class.getName());        Method[] methods = clazz.getDeclaredMethods();        for (Method method: methods) {            String methodModifier = getModifiers(method.getModifiers());            String methodName = method.getName();            String methodReturnType = method.getReturnType().getName();            Class<?>[] methodParam = method.getParameterTypes();            String methodParamName = "";            for (int i = 0; i < methodParam.length; i++) {                Class param = methodParam[i];                methodParamName = methodParamName + param.getName() + " arg"+i+",";            }            if (methodParamName.length() > 1) {                methodParamName = methodParamName.substring(0, methodParamName.length()-1);            }            methodParamName = "("+methodParamName+")";            System.out.println(methodModifier+" "+methodReturnType+" "+methodName +" "+methodParamName);        }    }    /**     * 獲取class對象     * @param clazzName     * @return     */    private static Class getClass(String clazzName) {        Class clazz = null;        try {            clazz = Class.forName(clazzName);        } catch (ClassNotFoundException e) {            e.printStackTrace();        }        return clazz;    }}

輸出結果：