初探 java反射机制

java可以通过反射机制获取类的各种信息和创建类的实例,就算将构造方法用private修饰,也可以创建,通过反射能创建很多强大的功能,算是写框架的常用方法和技巧

这里只介绍通过反射获取类的各种信息

实验类

package learn.reflect;public class UserBean {    private Integer id;    private String usrname;    private String phone;    public UserBean(Integer id, String usrname, String phone) {        super();        this.id = id;        this.usrname = usrname;        this.phone = phone;    }    public Integer getId() {        return id;    }    public void setId(Integer id) {        this.id = id;    }    public String getUsrname() {        return usrname;    }    public void setUsrname(String usrname) {        this.usrname = usrname;    }    public String getPhone() {        return phone;    }    public void setPhone(String phone) {        this.phone = phone;    }}

启动类

package learn.reflect;public class Main {    public static void main(String[] args) {        Class u = null;        try {            // 运行时加载以编译好的xxx.class文件,默认路径在classPath            u = Class.forName("learn.reflect.UserBean");            System.out.println("找到xxx.class文件");        } catch (ClassNotFoundException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        // 获取class后,能获取该类的一切信息进行判断或查看,有很多getxxx方法和isxxx方法        System.out.println("class文件和包路径: " + u.getName());        System.out.println(u.getComponentType());        System.out.println(u.getCanonicalName());        System.out.println(u.getModifiers());        System.out.println(u.getSimpleName());        System.out.println(u.getTypeName());        System.out.println(u.getAnnotatedInterfaces());        System.out.println(u.getAnnotatedSuperclass());        System.out.println(u.getAnnotations());        System.out.println(u.getConstructors());        System.out.println(u.getDeclaredAnnotations());        System.out.println(u.getFields());        System.out.println(u.getMethods());        System.out.println();        u.getMethods();    }}