package com.rao.domain;

import java.io.Serializable;
import java.util.Date;

/**
 * user表实体类
 *
 * @author Rao Hui
 * @date 2019-11-24 15:12
 */
public class User implements Serializable {

    private Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    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 "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", birthday=" + birthday +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

package com.rao.dao;

import com.rao.domain.User;
import org.apache.ibatis.annotations.Select;

import java.util.List;

/**
 * 用户的持久层接口
 *
 * @author Rao Hui
 * @date 2019-11-24 15:17
 */
public interface IUserDao {

    /**
     * 查询用户
     * @return
     */
    //@Select("select * from user") // 注解方式
    List<User> findAll();

    /**
     * 保存用户
     */
    void saveUser(User user);

    /**
     * 更新用户
     */
    void updateUser(User user);

    /**
     * 删除用户
     */
    void deleteUser(Integer userId);
}

package com.rao.test;

import com.rao.dao.IUserDao;
import com.rao.domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.util.List;

/**
 * mybatis入门测试
 *
 * @author Rao Hui
 * @date 2019-11-24 15:49
 */
public class MybatisTest {

    private InputStream in;
    private SqlSession session;
    private IUserDao userDao;

    @Before
    public void init() throws IOException
    {
        // 1. 读取配置文件
        in = Resources.getResourceAsStream("SqlMapConfig.xml");

        // 2. 创建SqlSessionFactory工厂
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(in);

        // 3. 使用工厂生产SqlSession对象
        session = factory.openSession();

        // 4. 使用SqlSession创建Dao接口的代理对象
        userDao = session.getMapper(IUserDao.class);
    }

    @After
    public void destroy() throws IOException
    {
        session.commit();

        // 释放资源
        session.close();
        in.close();
    }

    @Test
    public void testFindAll(){

        // 5. 使用代理对象执行方法
        List<User> users = userDao.findAll();
        for (User user : users)
        {
            System.out.println(user);
        }
    }

    @Test
    public void testSaveUser()
    {
        User user = new User();
        user.setUsername("hui");
        user.setSex("男");
        user.setAddress("山东省青岛市");
        user.setBirthday(new Date());

        userDao.saveUser(user);
    }

    @Test
    public void testUpdateUser()
    {
        User user = new User();
        user.setId(3);
        user.setUsername("liu");
        user.setSex("女");
        user.setAddress("山东省青岛市");
        user.setBirthday(new Date());

        userDao.updateUser(user);
    }

    @Test
    public void testDeleteUser()
    {
        userDao.deleteUser(4);
    }
}

/**
 * Book实体类
 *
 * @author Rao Hui
 * @date 2019-11-26 09:39
 */
public class Book {

    private final static String TAG = "BookTag";

    private String name;
    private String author;

    @Override
    public String toString() {
        return "Book{" +
                "name='" + name + '\'' +
                ", author='" + author + '\'' +
                '}';
    }

    public Book(){

    }

    public Book(String name, String author) {
        this.name = name;
        this.author = author;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    private String declareMethod(int index){
        String string = null;
        switch (index)
        {
            case 0:
                string = "I am declaredMethod 1 !";
                break;
            case 1:
                string = "I am declaredMethod 2 !";
                break;
            default:
                string = "I am declaredMethod 1 !";
        }

        return string;
    }
}

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

/**
 * Book实体类反射测试
 * @author Rao Hui
 * @date 2019-11-26 09:44
 */
public class ReflectBook {

    public static void main(String[] args){
        try {

            // 反射创建对象
            reflectNewInstance();

            // 反射私有构造方法
            reflectPrivateConstrcutor();

            // 反射私有方法
            reflectPrivateMethod();

            // 反射私有属性
            reflectPrivateField();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 反射创建对象
     */
    public static void reflectNewInstance() throws Exception
    {
        Class<?> classBook = Class.forName("Book");
        Object objectBook = classBook.newInstance();
        Book book = (Book)objectBook;
        book.setName("SRE运维解密");
        book.setAuthor("Google");
        System.out.println(book.toString());
    }

    /**
     * 反射私有构造方法
     */
    public static void reflectPrivateConstrcutor() throws Exception
    {
        Class<?> classBook = Class.forName("Book");
        Constructor<?> declaredConstructorBook = classBook.getDeclaredConstructor(String.class,String.class);

        //取消权限控制检查
        declaredConstructorBook.setAccessible(true);
        Book book = (Book)declaredConstructorBook.newInstance("高性能 MySQL", "hui");
        System.out.println(book.toString());
    }

    /**
     * 反射私有方法
     */
    public static void reflectPrivateMethod() throws Exception
    {
        Class<?> classBook = Class.forName("Book");
        Method method = classBook.getDeclaredMethod("declareMethod", int.class);
        method.setAccessible(true);

        // 传递object对象及参数调用该对象对应的方法
        String string = (String)method.invoke(classBook.newInstance(), 0);
        System.out.println(string);
    }

    /**
     * 反射私有属性
     */
    public static void reflectPrivateField() throws Exception
    {
        Class<?> classBook = Class.forName("Book");
        Object objectBook = classBook.newInstance();
        Field fieldTag = classBook.getDeclaredField("TAG");
        fieldTag.setAccessible(true);
        String tag = (String) fieldTag.get(objectBook);
        System.out.println(tag);
    }
}

double salary = 6500.0;
int vacationDays = 12;
long earthPopulation = xx;
boolean done = false;
Box box = new Box();

final double CM_PER_INCH = 2.54;

if (str.length() == 0)
if (str.equals(""))

if (str != null && str.length() != 0)

import java.util.*;

/**
 * This program demonstrates console input.
 * @version v1.0 2019-11-20
 * @author Rao Hui
 */
public class Demo {
    public static void main(String[] args)
    {
        Scanner in = new Scanner(System.in);

        // get frist input
        System.out.print("What is your name? ");
        String name = in.nextLine();

        // get second input
        System.out.print("How old are you? ");
        int age = in.nextInt();

        // dispaly output on console
        System.out.println("Hello, " + name + ". Next year, you'll be " + (age + 1));
    }
}

public class Test {
   public static void main(String args[]){
      int[] numbers = {10, 20, 30, 40, 50};
 
      for(int x : numbers ){
         System.out.print( x );
         System.out.print(",");
      }
      System.out.print("\n");
      String[] names ={"James", "Larry", "Tom", "Lacy"};
      for( String name : names ) {
         System.out.print( name );
         System.out.print(",");
      }
   }
}

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}

Hello World!