Junit優(yōu)點(diǎn)

public class TestDemo {
????//目標(biāo)：掌握如何獲取構(gòu)造器對(duì)象，并利用構(gòu)造器對(duì)象創(chuàng)建對(duì)象

????//獲取所有公共的構(gòu)造器對(duì)象
????@Test
????public void getConstructors(){
????????//1.獲得類對(duì)象
????????Class class1 = Student.class;
????????//2.獲得所有公共構(gòu)造器對(duì)象
????????Constructor[] constructors = class1.getConstructors();
????????//3.遍歷構(gòu)造器數(shù)組
????????for (Constructor constructor : constructors) {
????????????System.out.println(constructor.getName()+"===>"+constructor.getParameterCount());
????????}
????}

????//獲取所有的構(gòu)造器對(duì)象，無論構(gòu)造器是公開的，還是私有的
????@Test
????public void getDeclaredConstructors(){
????????//1.獲取類對(duì)象
????????Class class2 = Student.class;
????????//2.獲取所有構(gòu)造器對(duì)象
????????Constructor[] allConstructor = class2.getDeclaredConstructors();
????????//3.遍歷構(gòu)造器對(duì)象
????????for (Constructor constructor : allConstructor) {
????????????System.out.println(constructor.getName()+"===>"+constructor.getParameterCount());
????????}
????}

????//獲取單個(gè)構(gòu)造器對(duì)象
????@Test
????public void getConstructor() throws Exception{
????????//1.獲取類對(duì)象
????????Class class3 = Student.class;
????????//2.獲取單個(gè)構(gòu)造器
????????Constructor constructor = class3.getDeclaredConstructor(String.class,int.class);
????????constructor.setAccessible(true);
????????//3.通過這個(gè)構(gòu)造器創(chuàng)建對(duì)象
????????Student s = (Student) constructor.newInstance("張三",12);
????????System.out.println(s);

????}

????//獲取單個(gè)構(gòu)造器對(duì)象,無視構(gòu)造器的訪問權(quán)限
????@Test
????public void getDeclaredConstructor() throws Exception{
????????//1.獲取類對(duì)象
????????Class class3 = Student.class;
????????//2.獲取單個(gè)構(gòu)造器
????????Constructor constructor = class3.getDeclaredConstructor();
????????//3.暴力反射
????????constructor.setAccessible(true);
????????//4.通過這個(gè)構(gòu)造器創(chuàng)建對(duì)象
????????Student student = (Student) constructor.newInstance();
????????System.out.println(student);
????}
}

2.5?反射獲取成員變量對(duì)象

public class FieldDemo1 {
????//目標(biāo)：掌握成員變量對(duì)象的獲取，并對(duì)某個(gè)對(duì)象中相應(yīng)的成員變量進(jìn)行取值和賦值

????//通過反射獲取所有成員變量對(duì)象
????@Test
????public void getFields() throws Exception {
????????//1.獲取類對(duì)象
????????Class class1 = Student.class;
????????//2.獲取所有成員變量對(duì)象
????????Field[] fields = class1.getDeclaredFields();
????????//3.遍歷所有成員變量對(duì)象
????????for (Field field : fields) {
????????????System.out.println(field.getName()+"===>"+field.getType());
????????}

????}

????//通過反射獲取一個(gè)成員變量并賦值
????@Test
????public void getField() throws Exception {
????????//1.獲取類對(duì)象
????????Class class1 = Student.class;
????????//2.獲取成員變量對(duì)象
????????Field name = class1.getDeclaredField("name");
????????//3.暴力反射
????????name.setAccessible(true);
????????//4.對(duì)成員變量賦值
????????Student s = new Student();
????????name.set(s,"張三");
????????//5.打印對(duì)象
????????System.out.println(s);
????}

????//通過反射獲取一個(gè)成員變量并取值
????@Test
????public void getField2() throws Exception {
????????//1.獲取類對(duì)象
????????Class class1 = Student.class;
????????//2.獲取成員變量對(duì)象
????????Field name = class1.getDeclaredField("name");
????????//3.暴力反射
????????name.setAccessible(true);
????????//4.對(duì)成員變量取值
????????Student s = new Student("李四",12);
????????String s1 = (String) name.get(s);
????????//5.打印成員變量
????????System.out.println(s1);
????}
}

2.6?反射獲取成員方法對(duì)象

//框架代碼：
public class MyBatisUtils {
????public static void save(Object o){
????????try (
????????????????PrintStream ps = new PrintStream(new FileOutputStream("junit-reflect-annotation-proxy/src/reflect.txt",true))
????????????????){
????????????//1.得到類對(duì)象
????????????Class aClass = o.getClass();
????????????ps.println("================="+aClass.getSimpleName()+"=================");
????????????//2.得到類中全部的成員變量對(duì)象
????????????Field[] fields = aClass.getDeclaredFields();
????????????//3.得到全部成員變量對(duì)象的名字和值

????????????for (Field field : fields) {
????????????????field.setAccessible(true);
????????????????String name = field.getName();
????????????????String??value = field.get(o)+" ";
????????????????//4.保存到文件中
????????????????ps.println(name+"---"+value);
????????????}
????????} catch (Exception e) {
????????????e.printStackTrace();
????????}
????}
}

//測(cè)試代碼：
public class ReflectDemo1 {
????public static void main(String[] args) {
????????//目標(biāo)：利用反射技術(shù)，做一個(gè)通用框架
????????//向?qū)ο笾刑砑訑?shù)據(jù)，并將對(duì)象傳到框架中
????????Student s = new Student("張三",17,'男',12,"3000");
????????MyBatisUtils.save(s);

????????Tercher t = new Tercher("張三",17,'男',"王標(biāo)");
????????MyBatisUtils.save(t);

????}
}