package cn.itcast.demo;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.ArrayList;import java.util.List;public class Demo1 {    public static void main(String[] args) throws SecurityException, NoSuchMethodException, IllegalArgumentException, IllegalAccessException, InvocationTargetException {        // 定义一个List<Integer>        List<Integer> list = new ArrayList<Integer>();        // 添加一个字符串 "abc"        // list.add("abc");        // 解决问题,使用反射        // 1.得到List的Class。        Class clazz = list.getClass();                //2.通过clazz去获取add方法.        Method addMethod=clazz.getMethod("add", Object.class);                //3.调用add方法，将"abc"添加.                addMethod.invoke(list, "abc");                System.out.println(list);    }}

package cn.itcast.demo;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import org.junit.Test;//获取对象public class Demo2 {    // 1.new    @Test    public void fun1() {        Person p = new Person();    }    // 使用反射    @Test    public void fun2() throws ClassNotFoundException, InstantiationException,            IllegalAccessException {        Class c = Class.forName("cn.itcast.demo.Person");        c.newInstance();    }    // 3.使用IO流.    @Test    public void fun3() throws FileNotFoundException, IOException {        // 将一个对象写入到object.txt文件中.        Person p = new Person();        p.setName("tom");        p.setSex("male");        p.setAddress("北京");        // 在java中如果描述路径要使用 两个\\,也可以使用一个/。        File file = new File("D:/java0106/workspace/day02/src/object.txt");        // // 绝对路径        // 相对路径        // File file=new File("src/object.txt");        // 在开发中获取classpath路径。 获取我们的classpath路径的根目录. 那么如果文件存在于bin中，就可以直接在后面写路径        // String path = Demo2.class.getResource("/object.txt").getPath();        // File file=new File(path);        // System.out.println(file.exists());        writeObjectToFile(p, file);    }    @Test    public void fun4() throws FileNotFoundException, IOException,            ClassNotFoundException {        File file = new File("D:/java0106/workspace/day02/src/object.txt");        Person p = (Person) readObjectFromFile(file);        System.out.println(p);    }    // 从文件中读取对象    private Object readObjectFromFile(File file) throws FileNotFoundException,            IOException, ClassNotFoundException {        ObjectInputStream ois = new ObjectInputStream(new FileInputStream(file));        Object obj = ois.readObject();        ois.close();        return obj;    }    // 将对象写入到文件中的操作    private void writeObjectToFile(Object obj, File file)            throws FileNotFoundException, IOException {        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(                file));        oos.writeObject(obj);        oos.flush();        oos.close();    }    // 使用克隆    @Test    public void fun5() throws CloneNotSupportedException {        Person p = new Person();        p.setName("tom");        p.setSex("male");        p.setAddress("北京");                        Person pp = (Person) p.clone(); // 得到一个p对象的副本                System.out.println(pp);    }}

package cn.itcast.demo;import java.io.Serializable;public class Person implements Cloneable{// implements Serializable {    // private static final long serialVersionUID = 1L;    private String name;    private String sex;    private String address;    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getSex() {        return sex;    }    public void setSex(String sex) {        this.sex = sex;    }    public String getAddress() {        return address;    }    public void setAddress(String address) {        this.address = address;    }    @Override    public String toString() {        return "Person [name=" + name + ", sex=" + sex + ", address=" + address                + "]";    }    @Override    public Object clone() throws CloneNotSupportedException {        return super.clone();    }}

package cn.itcast.demo;import java.lang.reflect.Field;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.HashMap;import java.util.Map;import java.util.Set;import org.junit.Test;public class Demo3 {    public static void main(String[] args) throws SecurityException,            NoSuchMethodException, IllegalArgumentException, IllegalAccessException, InvocationTargetException {        Map<String, String> map = new HashMap<String, String>();        map.put("name", "tom");        map.put("sex", "男");        map.put("address", "北京");        Person p = new Person();        // 1.得到集合中的所有key        Set<String> keys = map.keySet();        // 2.得到所有的Person类中的属性.        Class clazz = p.getClass();        Field[] fields = clazz.getDeclaredFields();// 属性是private        // 3.遍历属性，判断keys是否包含这些属性.        for (Field field : fields) {            // 得到属性名称.            String fieldName = field.getName();            if (keys.contains(fieldName)) {                // map集合的key中包含这样的属性名。那么就需要调用这个属性对应的set方法将key对应的value进行赋值操作.                // 1.得到value                String value =http://www.mamicode.com/ map.get(fieldName);                // 2.得到属性对应的set方法                Method setMethod = clazz.getMethod(getSetMethodName(fieldName),                        String.class);                                //3.调用方法进行赋值.                                setMethod.invoke(p, value);            }        }                System.out.println(p);    }    public static String getSetMethodName(String param) {        return "set" + (char) (param.charAt(0) - 32) + param.substring(1);    }    @Test    public void fun() {        // ‘n‘---->N        System.out.println((char) (‘n‘ - 32));    }}