JAVA反射机制实例代码(转)

首先在工程中建立 一个Bean类

public class UserBean {
    private String userName ="admin";
    private String passWord = "888";
    public String getPassWord() {
        return passWord;
    }
    public void setPassWord(String passWord) {
        this.passWord = passWord;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public void setUserName(int i) {

    }
}

然后 新建一个类 main.java

import java.lang.reflect.Field;
import java.lang.reflect.Method;

public class Main {

    //根据字段调用所有的set方法，传入死值 love

    private void dox8() throws Exception {
        // TODO Auto-generated method stub


        Class cls = Class.forName("com.accp.UserBean");
        Object o = cls.newInstance();

        Field[] fields = cls.getDeclaredFields();

        for (Field field : fields) {
            String fieldName = field.getName();

            Method method = cls.getDeclaredMethod("set"+fieldName.substring(0,1).toUpperCase()+fieldName.substring(1),new Class[]{String.class});
            method.invoke(o, new Object[]{"love"});
        }

        UserBean bean = (UserBean)o;

        System.out.println(bean.getUserName()+" "+bean.getPassWord());

    }

    private void dox7() throws Exception
    {
        Class cls = Class.forName("com.accp.UserBean");
        Object o = cls.newInstance();

        Method m = cls.getDeclaredMethod("setUserName",new Class[]{String.class});

        m.invoke(o,new Object[]{"John.Lenoe"});


        UserBean bean = (UserBean)o;

        System.out.println(bean.getUserName());

    }

    //通过字段找方法

    private void dox6() throws Exception {
        // TODO Auto-generated method stub

        Class cls = Class.forName("com.accp.UserBean");
        Object o = cls.newInstance();

        Field field = cls.getDeclaredField("userName");

        String fieldName = field.getName();

        Method method = cls.getDeclaredMethod("get"+fieldName.substring(0,1).toUpperCase()+fieldName.substring(1));

    }

    //调用其中一个已知方法名的方法

    private void dox5() throws Exception {
        // TODO Auto-generated method stub

        Class cls = Class.forName("com.accp.UserBean");
        Object obj = cls.newInstance();

        Method method = cls.getDeclaredMethod("getUserName");
        Object o = method.invoke(obj);
        System.out.println(o);
    }

    //调用当前类的所有get方法

    private void dox4() throws Exception {
        // TODO Auto-generated method stub

        Class cls = Class.forName("com.accp.UserBean");
        Object obj = cls.newInstance();
        Method[] methods = cls.getDeclaredMethods();

        for (Method method : methods) {
            if(method.getName().startsWith("get"))
            {
                Object temp = method.invoke(obj);
                System.out.println(temp);
            }
        }

    }

    //取出当前类中所有的方法

    private void dox3() throws Exception {
        // TODO Auto-generated method stub

        Class cls = Class.forName("com.accp.UserBean");
        Method[] methods = cls.getDeclaredMethods();

        for (Method method : methods) {
            System.out.println(method.getName()+" "+method.getReturnType());
        }
    }


    //取出当前类中所有的字段

    private void dox2() throws ClassNotFoundException {
        // TODO Auto-generated method stub

        Class cls = Class.forName("com.accp.UserBean");

        Field[] fields = cls.getDeclaredFields();

        for (int i = 0; i < fields.length; i++) {
            Field field = fields[i];
            System.out.println(field.getName()+" "+field.getType());
        }

    }

    public static void main(String[] args) throws Exception {
        Main ma = new Main();
        ma.dox8();
    }

    //根据传入的类名，生成类结构和类实例

    private void dox() throws Exception {
        // TODO Auto-generated method stub

        Class cls = Class.forName("com.accp.UserBean");
        Object obj = cls.newInstance();
        UserBean bean = (UserBean)obj;

        bean.setUserName("admin");
        System.out.println(bean.getUserName());
    }
}

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