SSM-MyBatis-02：Mybatis最基础的增删改查（查全部和查单独一个）

------------吾亦无他,唯手熟尔，谦卑若愚，好学若饥-------------

继续上次的开始，这次记录的是增删改查，上次重复过的代码不做过多解释

首先先创建mysql的表和实体类Book

BOOK

package cn.dawn.demo01.entity;

public class Book {
    private Integer bookID;
    private String bookName;
    private String bookAuthor;
    private Integer bookPrice;

    public Book() {
    }

    public Integer getBookID() {
        return this.bookID;
    }

    public void setBookID(Integer bookID) {
        this.bookID = bookID;
    }

    public String getBookName() {
        return this.bookName;
    }

    public void setBookName(String bookName) {
        this.bookName = bookName;
    }

    public String getBookAuthor() {
        return this.bookAuthor;
    }

    public void setBookAuthor(String bookAuthor) {
        this.bookAuthor = bookAuthor;
    }

    public Integer getBookPrice() {
        return this.bookPrice;
    }

    public void setBookPrice(Integer bookPrice) {
        this.bookPrice = bookPrice;
    }
}

接下来是接口，我写到一块了，一次全部拿出来，我会标清除注释，给解释一下

package cn.dawn.demo01.dao;

import cn.dawn.demo01.entity.Book;

import java.util.List;

/**
 * Created by Dawn on 2018/1/29.
 */
public interface IBookDAO {
    //查全部
    public List<Book> findAllBook();
    //添加
    public int insertBook(Book book);
    //删除
    public int deleteBook(int id);
    //修改
    public int updateBook(Book book);
    //查都单独
    public Book findOneBookByPK(int id);
}

增删改得到的返回值都是受影响的行数，查全部返回List泛型，查单独根据bookid进行查，返回的是单个对象Book

接下来是dao层同名的xml中

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.dawn.demo01.dao.IBookDAO">
    <select id="findAllBook" resultType="Book">
        select * from book
    </select>
    <insert id="insertBook">
        INSERT  INTO book(bookname,bookauthor,bookprice) VALUES (#{bookName},#{bookAuthor},#{bookPrice})
    </insert>
    <update id="updateBook">
        UPDATE  book SET bookname=#{bookName},bookauthor=#{bookAuthor},bookprice=#{bookPrice} WHERE  bookid=#{bookID}
    </update>
    <delete id="deleteBook">
        DELETE FROM book WHERE bookid=#{bookID}
    </delete>
    <select id="findOneBookByPK" resultType="Book">
        SELECT * FROM book WHERE bookid=#{bookID}
    </select>
</mapper>

下面我说一下这个xml中要注意的点，

mapper中的属性namespace的值就是刚才和这个同名的dao的全类名

其中的id要写成你刚才那个接口里的方法名，mybatis的这种方法这儿需要这么干，resultType="Book"，这儿他是返回值类型，他这儿默认得写全类名，例如"cn.dawn.day01.entity.Book",

但是我这儿经过一个处理，它可以直接写成book，这个小知识点叫别名，稍微引一下，这儿放截图，截图好理解

 parameterType=""这儿这个属性，我上面省略掉了，他的意思是什么呢，就是传进去的参数类型，刚才不是有个带参方法是根据id拿到所对应的书吗，这就可以写id的类型，但是这儿可以省略，所以我就不写了

准备工作都做完成之后，我们开始用单测的方式来进行单测

我下面把单测的方法放上来，使用的是较为原始的方式，更直接的剖析

import cn.dawn.demo01.entity.Book;
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.Test;

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

/**
 * Created by Dawn on 2018/1/29.
 */
public class Test20180129 {

    /*Logger logger=Logger.getLogger("xxx");*/
    ///查单独
    @Test
    public void t5findOne(){
        /*logger.info("这是查单独");*/
        String path = "mybatis-config.xml";

        try {
            InputStream e = Resources.getResourceAsStream(path);
            SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
            SqlSessionFactory factory = builder.build(e);
            SqlSession session = factory.openSession();

            Book book = session.selectOne("findOneBookByPK", );
            System.out.println("书名"+book.getBookName());

            session.close();
        } catch (IOException var9) {
            var9.printStackTrace();
        }
    }

    ///删除
    @Test
    public void t4delete(){
        String path = "mybatis-config.xml";

        try {
            InputStream e = Resources.getResourceAsStream(path);
            SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
            SqlSessionFactory factory = builder.build(e);
            SqlSession session = factory.openSession();

            int count123 = session.delete("deleteBook",);
            session.commit();
            System.out.println(count123);

            session.close();
        } catch (IOException var9) {
            var9.printStackTrace();
        }
    }

    ///修改
    @Test
    public void t3update(){
        String path = "mybatis-config.xml";

        try {
            InputStream e = Resources.getResourceAsStream(path);
            SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
            SqlSessionFactory factory = builder.build(e);
            SqlSession session = factory.openSession();

            Book book=new Book();
            book.setBookID();
            book.setBookName("心想事成888");

            int count123 = session.update("updateBook", book);
            session.commit();
            System.out.println(count123);

            session.close();
        } catch (IOException var9) {
            var9.printStackTrace();
        }
    }

    ///添加
    @Test
    public void t2Insert(){
        String path = "mybatis-config.xml";

        try {
            InputStream e = Resources.getResourceAsStream(path);
            SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
            SqlSessionFactory factory = builder.build(e);
            SqlSession session = factory.openSession();

            Book book=new Book();
            book.setBookName("心想事成");
            book.setBookAuthor("孟六");
            book.setBookPrice();

            int count123 = session.insert("insertBook", book);
            session.commit();
            System.out.println(count123);

            session.close();
        } catch (IOException var9) {
            var9.printStackTrace();
        }
    }

    ///查全部
    @Test
    public void t1SelectAll(){
        String path = "mybatis-config.xml";

        try {
            InputStream e = Resources.getResourceAsStream(path);
            SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
            SqlSessionFactory factory = builder.build(e);
            SqlSession session = factory.openSession();
            List lists = session.selectList("findAllBook");
            Iterator var7 = lists.iterator();

            while(var7.hasNext()) {
                Book book = (Book)var7.next();
                System.out.println(book.getBookName() + "\t" + book.getBookAuthor());
            }

            session.close();
        } catch (IOException var9) {
            var9.printStackTrace();
        }
    }
}

只有selectOne需要看一下，他是查单个的意思，别的都比较好理解，有的前一个博客有写，有的从字面意思就可以理解

增删改查就此结束