68.7 反射的作用：通用框架的底层原理

package com.itheima.d7_reflect_framework;
/**
   目标：提供一个通用框架，支持保存所有对象的具体信息。
 */
public class ReflectDemo {
    public static void main(String[] args) throws Exception {
        Student s = new Student();
        s.setName("猪八戒");
        s.setClassName("西天跑路1班");
        s.setAge(1000);
        s.setHobby("吃，睡");
        s.setSex('男');
        MybatisUtil.save(s);
        Teacher t = new Teacher();
        t.setName("波仔");
        t.setSex('男');
        t.setSalary(6000);
        MybatisUtil.save(t);
    }
}

package com.itheima.d7_reflect_framework;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.lang.reflect.Field;
public class MybatisUtil {
    /**
     保存任意类型的对象
     * @param obj
     */
    public static void save(Object obj){
        try (
                PrintStream ps = new PrintStream(new FileOutputStream("junit-reflect-annotation-proxy-app/src/data.txt", true));
        ){
            // 1、提取这个对象的全部成员变量：只有反射可以解决
            Class c = obj.getClass();  //   c.getSimpleName()获取当前类名   c.getName获取全限名：包名+类名
            ps.println("================" + c.getSimpleName() + "================");
            // 2、提取它的全部成员变量
            Field[] fields = c.getDeclaredFields();
            // 3、获取成员变量的信息
            for (Field field : fields) {
                String name = field.getName();
                // 提取本成员变量在obj对象中的值（取值）
                field.setAccessible(true);
                String value = field.get(obj) + "";
                ps.println(name  + "=" + value);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

package com.itheima.d7_reflect_framework;
public class Student {
    private String name;
    private char sex;
    private int age;
    private String className;
    private String hobby;
    public Student(){
    }
    public Student(String name, char sex, int age, String className, String hobby) {
        this.name = name;
        this.sex = sex;
        this.age = age;
        this.className = className;
        this.hobby = hobby;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public char getSex() {
        return sex;
    }
    public void setSex(char sex) {
        this.sex = sex;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getClassName() {
        return className;
    }
    public void setClassName(String className) {
        this.className = className;
    }
    public String getHobby() {
        return hobby;
    }
    public void setHobby(String hobby) {
        this.hobby = hobby;
    }
}

package com.itheima.d7_reflect_framework;
public class Teacher {
    private String name;
    private char sex;
    private double salary;
    public Teacher(){
    }
    public Teacher(String name, char sex, double salary) {
        this.name = name;
        this.sex = sex;
        this.salary = salary;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public char getSex() {
        return sex;
    }
    public void setSex(char sex) {
        this.sex = sex;
    }
    public double getSalary() {
        return salary;
    }
    public void setSalary(double salary) {
        this.salary = salary;
    }
}