说明

参考内容：

1、反射机制，调用属性（静态&非静态）；2、反射机制，调用构造方法（静态&非静态）。

getter/setter方法

定义一些方法来操作成员变量，每个方法都必须有一个有意义的名称，所以就有了getter-setter方法，getter-setter方法格式和写法都是固定的，所以只要有getter-setter方法就不用煞费心思的去想方法名称了，解决了起名字难问题。并且getter-setter方法还是程序员之间的一种规范，给属性赋值立刻就会想到getter-setter方法，降低了程序员之间的沟通成本。

代码案例

工具类：

import org.apache.commons.lang3.StringUtils;import java.lang.reflect.Method;import java.util.List;public class ReflectCallMethod {    /**     * @param entryClass     * @param methodName     * @param <T>     * @return     */    public static <T> T invokeForStatic(Class entryClass, String methodName) {        if (entryClass == null) {            return null;        }        T result = null;        try {            // 反射获取            Method method = entryClass.getDeclaredMethod(methodName);            method.setAccessible(true);            return (T) method.invoke(entryClass);        } catch (Exception e) {            e.printStackTrace();        }        return result;    }    /**     * @param entryClass     * @param methodName     * @param classArgs     * @param valueArgs     * @param <T>     * @return     */    public static <T> T invokeForStatic(Class entryClass, String methodName, Class[] classArgs, Object[] valueArgs) {        if (entryClass == null) {            return null;        }        T result = null;        try {            Method method = entryClass.getDeclaredMethod(methodName, classArgs);            method.setAccessible(true);            return (T) method.invoke(entryClass, valueArgs);        } catch (Exception e) {            e.printStackTrace();        }        return result;    }    /**     * @param entryClass     * @param methodName     * @param initArgs     * @param <T>     * @return     */    public static <T> T invokeForStatic(Class entryClass, String methodName, List<Object> initArgs) {        if (entryClass == null) {            return null;        }        T result = null;        try {            Class[] classArgs = new Class[initArgs.size()];            Object[] valueArgs = new Object[initArgs.size()];            for (int i = 0; i < initArgs.size(); i++) {                classArgs[i] = initArgs.get(i).getClass();                valueArgs[i] = initArgs.get(i);            }            Method method = entryClass.getDeclaredMethod(methodName, classArgs);            method.setAccessible(true);            return (T) method.invoke(entryClass, valueArgs);        } catch (Exception e) {            e.printStackTrace();        }        return result;    }    /**     * @param entryObject     * @param methodName     * @param <T>     * @return     */    public static <T> T invokeForInstance(Object entryObject, String methodName) {        if (entryObject == null) {            return null;        }        T result = null;        try {            // 反射获取            Method method = entryObject.getClass().getDeclaredMethod(methodName);            method.setAccessible(true);            return (T) method.invoke(entryObject);        } catch (Exception e) {            e.printStackTrace();        }        return result;    }    /**     * @param entryObject     * @param methodName     * @param classArgs     * @param valueArgs     * @param <T>     * @return     */    public static <T> T invokeForInstance(Object entryObject, String methodName, Class[] classArgs, Object[] valueArgs) {        if (entryObject == null) {            return null;        }        T result = null;        try {            Method method = entryObject.getClass().getDeclaredMethod(methodName, classArgs);            method.setAccessible(true);            return (T) method.invoke(entryObject, valueArgs);        } catch (Exception e) {            e.printStackTrace();        }        return result;    }    /**     * @param entryObject     * @param methodName     * @param initArgs     * @param <T>     * @return     */    public static <T> T invokeForInstance(Object entryObject, String methodName, List<Object> initArgs) {        if (entryObject == null) {            return null;        }        T result = null;        try {            Class[] classArgs = new Class[initArgs.size()];            Object[] valueArgs = new Object[initArgs.size()];            for (int i = 0; i < initArgs.size(); i++) {                classArgs[i] = initArgs.get(i).getClass();                valueArgs[i] = initArgs.get(i);            }            Method method = entryObject.getClass().getDeclaredMethod(methodName, classArgs);            method.setAccessible(true);            return (T) method.invoke(entryObject, valueArgs);        } catch (Exception e) {            e.printStackTrace();        }        return result;    }    //=============================================================================================//    // getter and setter    //=============================================================================================//    /**     * @param entryObject     * @param methodName     * @param <E>     * @return     */    public static <E> E getInvoke(Object entryObject, String methodName) {        if (entryObject == null || StringUtils.isEmpty(methodName)) {            return null;        }        try {            Method method = entryObject.getClass().getDeclaredMethod(methodName);            method.setAccessible(true);            Object returnValue = method.invoke(entryObject);            return (E) returnValue;        } catch (Exception ex) {            ex.printStackTrace();        }        return null;    }    /**     * @param entryObject     * @param fieldName     * @param <E>     * @return     */    public static <E> E getInvokeByFieldName(Object entryObject, String fieldName) {        if (entryObject == null || StringUtils.isEmpty(fieldName)) {            return null;        }        try {            String methodName = "get" + StringUtils.capitalize(fieldName);            Method method = entryObject.getClass().getDeclaredMethod(methodName);            method.setAccessible(true);            Object returnValue = method.invoke(entryObject);            return (E) returnValue;        } catch (Exception ex) {            ex.printStackTrace();        }        return null;    }    /**     * @param entryObject     * @param methodName     * @param <E>     * @return     */    public static <E> E setInvoke(Object entryObject, String methodName, Object object) {        if (entryObject == null || StringUtils.isEmpty(methodName)) {            return null;        }        try {            Method method = entryObject.getClass().getDeclaredMethod(methodName, object.getClass());            method.setAccessible(true);            Object returnValue = method.invoke(entryObject, object);            return (E) returnValue;        } catch (Exception ex) {            ex.printStackTrace();        }        return null;    }    /**     * @param entryObject     * @param fieldName     * @param <E>     * @return     */    public static <E> E setInvokeByFieldName(Object entryObject, String fieldName, Object object) {        if (entryObject == null || StringUtils.isEmpty(fieldName)) {            return null;        }        try {            String methodName = "set" + StringUtils.capitalize(fieldName);            Method method = entryObject.getClass().getDeclaredMethod(methodName, object.getClass());            method.setAccessible(true);            Object returnValue = method.invoke(entryObject, object);            return (E) returnValue;        } catch (Exception ex) {            ex.printStackTrace();        }        return null;    }    //=============================================================================================//    // the end    //=============================================================================================//}

测试类：

import lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor;import java.io.Serializable;import java.util.Date;import java.util.HashMap;import java.util.Map;@Data@AllArgsConstructor@NoArgsConstructorpublic class User implements Serializable, Cloneable {    private Integer id;    private String name;    private Date createTime;    /**     * 静态方法1     */    public static void testCall1() {        System.out.println("testCall.1");    }    /**     * 静态方法2     * @param paramsMap     * @return     */    public static Map<String, Object> testCall2(Map<String, Object> paramsMap) {        System.out.println("testCall.2," + paramsMap);        return paramsMap;    }    /**     * 静态方法     * @param paramsMap     * @return     */    public static Map<String, Object> testCall3(HashMap<String, Object> paramsMap) {        System.out.println("testCall.3," + paramsMap);        return paramsMap;    }    /**     * 实例方法1     */    public void testCall11() {        System.out.println("testCall.11");    }    /**     * 实例方法2     * @param paramsMap     * @return     */    public Map<String, Object> testCall12(Map<String, Object> paramsMap) {        System.out.println("testCall.12," + paramsMap);        return paramsMap;    }    /**     * 实例方法3     * @param paramsMap     * @return     */    public Map<String, Object> testCall13(HashMap<String, Object> paramsMap) {        System.out.println("testCall.13," + paramsMap);        return paramsMap;    }}

import java.util.Arrays;import java.util.Date;import java.util.HashMap;import java.util.Map;public class ReflectCallMethodDemo {    public static void main(String[] args) {        // 静态方法调用=====1        Object result1 = ReflectCallMethod.invokeForStatic(User.class, "testCall1");        System.out.println("result1 is null ," + result1);        // 静态方法调用=====2        Map<String, Object> paramsMap1 = new HashMap<>();        paramsMap1.put("map", new Object());        Map<String, Object> result2 = ReflectCallMethod.invokeForStatic(User.class, "testCall2",                new Class[]{Map.class}, new Object[]{paramsMap1});        System.out.println("result2 is map ," + result2);        // 静态方法调用=====3        Map<String, Object> result3 = ReflectCallMethod.invokeForStatic(User.class, "testCall3", Arrays.asList(paramsMap1));        System.out.println("result3 is map ," + result3);        // 实例方法调用1        User user = new User();        Object result11 = ReflectCallMethod.invokeForInstance(user, "testCall11");        System.out.println("result11 is null ," + result11);        // 实例方法调用=====2        Map<String, Object> paramsMap21 = new HashMap<>();        paramsMap1.put("map", new Object());        Map<String, Object> result12 = ReflectCallMethod.invokeForInstance(user, "testCall12",                new Class[]{Map.class}, new Object[]{paramsMap21});        System.out.println("result12 is map ," + result2);        // 实例方法调用=====3        Map<String, Object> result13 = ReflectCallMethod.invokeForInstance(user, "testCall13", Arrays.asList(paramsMap21));        System.out.println("result13 is map ," + result13);        // setter and getter        User user2 = new User(2, "子贡", new Date());        String name = ReflectCallMethod.getInvoke(user2, "getName");        System.out.println("method name get ," + name);        String name2 = ReflectCallMethod.getInvokeByFieldName(user2, "name");        System.out.println("field name get ," + name2);        ReflectCallMethod.setInvoke(user2, "setName", "闵损");        ReflectCallMethod.setInvokeByFieldName(user2, "id", 200);        int id = ReflectCallMethod.getInvoke(user2, "getId");        System.out.println("method name get ," + id);        String name3 = ReflectCallMethod.getInvokeByFieldName(user2, "name");        System.out.println("field name get ," + name3);    }}