MyBatis基本例子-實現增刪改查

1，項目結構

 

2，表單結構

 

 

3.代碼

package com.entity;

public class Book {

    private int bookid;
    private String bookname;
    private String bookauthor;
    private int bookprice;

    public Book() {
        super();
    }

    public Book(int bookid, String bookname, String bookauthor, int bookprice) {
        super();
        this.bookid = bookid;
        this.bookname = bookname;
        this.bookauthor = bookauthor;
        this.bookprice = bookprice;
    }

    public Book(String bookname, String bookauthor, int bookprice) {
        super();
        this.bookname = bookname;
        this.bookauthor = bookauthor;
        this.bookprice = bookprice;
    }

    public int getBookid() {
        return bookid;
    }

    public void setBookid(int bookid) {
        this.bookid = bookid;
    }

    public String getBookname() {
        return bookname;
    }

    public void setBookname(String bookname) {
        this.bookname = bookname;
    }

    public String getBookauthor() {
        return bookauthor;
    }

    public void setBookauthor(String bookauthor) {
        this.bookauthor = bookauthor;
    }

    public int getBookprice() {
        return bookprice;
    }

    public void setBookprice(int bookprice) {
        this.bookprice = bookprice;
    }

}

BookMapper.xml

<?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="com.mapper.BookMapper">

<span style="white-space:pre">    </span><resultMap id="mapBook" type="com.entity.Book">
        <id property="bookid" column="id"></id>
        <result property="bookname" column="username"></result>
        <result property="bookprice" column="price"></result>
        <result property="bookauthor" column="author"></result>
    </resultMap></span></strong>

    <select id="findById" parameterType="int" resultMap="mapBook">
        select *
        from book where id = #{id}
    </select>

    <delete id="del" parameterType="int">
        delete * from book where id =
        #{id}
    </delete>

    <insert id="add" parameterType="com.entity.Book">
        insert into book
        values(null,#{bookname},#{bookauthor},#{bookprice})
    </insert>

    <select id="show" resultMap="mapBook">
        select * from book
    </select>

</mapper>

Configuration.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"></property>
                <property name="url" value="jdbc:mysql://localhost:3306/<span style="color:#ff6666;"><mysqlDb></span>?characterEncoding=utf-8"></property>
                <property name="username" value=mysqlnam"></property>
                <property name="password" value="mysqlpassword"></property>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="com/mapper/BookMapper.xml"></mapper>
    </mappers>
</configuration>

 

3.4 MysqlSessionFactory

package com.util;

import java.io.IOException;
import java.io.Reader;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;


public class MysqlSessionFactory {
    static SqlSession session;
    public SqlSession getSqlSession(){
        try {
            Reader reader = Resources.getResourceAsReader("Configuration.xml");
            SqlSessionFactory  sessionFactory = new SqlSessionFactoryBuilder().build(reader);
            session = sessionFactory.openSession();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return session;
    }

}

Test.java

package com.util;

import org.apache.ibatis.session.SqlSession;

import com.entity.*;

public class Test {

    public static void main(String[] args) {

        MysqlSessionFactory mysqlSessionFactory = new MysqlSessionFactory();
        SqlSession session = mysqlSessionFactory.getSqlSession();

        System.out.println(session);

        Book book = (Book)session.selectOne("com.mapper.BookMapper.findById",25);
        System.out.println(book);
        session.commit();


        Book bookadd = new Book(0, "java","mike",90);
        session.insert("com.mapper.BookMapper.add",bookadd);
        session.commit();




    }

}

以上是整個demo的全部源代碼！

 

 

只想說這一部分

 

1,book.javav中的屬性名與mysql中book table中字段名字不匹配：

<resultMap id="mapBook" type="com.entity.Book">
    <id property="bookid" column="id"></id>
    <result property="bookname" column="username"></result>
    <result property="bookprice" column="price"></result>
    <result property="bookauthor" column="author"></result>
</resultMap>

resulteMap   是爲了解決book.javav中的屬性名與mysql中book table中字段名字不匹配，沒法進行數據的填充！

 

2,命名空間

<mapper namespace="com.mapper.BookMapper">

這個是service的名字，不要寫錯，另外service的方法名也要和配置文件的方法名同樣。

 

整體感受沒什麼好說的！

1，讀取配置文件得到SqlsessionFactory

2，經過SqlsessionFactory得到sqlsession

那涉及到一個問題：配置文件

配置文件:Configtion.xml

這個文件定義了關於數據源的配置

 

<environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"></property>
                <property name="url" <span style="font-family: Arial, Helvetica, sans-serif;">value="jdbc:mysql://localhost:3306/</span><span style="font-family: Arial, Helvetica, sans-serif;"></property></span>

            <property name="username" value="mysqlnam"></property>
            <property name="password" value="mysqlpassword"></property>
        </dataSource>
    </environment>
</environments>

那麼這裏有了鏈接mysql數據庫的必要信息可是咱們的目的是經過java語句操做數據庫

封裝數據庫爲一個POJO，也就是book.java

咱們經過操做book對象操做數據庫的記錄！

 

那麼類有了就會有類與數據庫中表的關係的對應配置信息BookMapper.xml

其實這裏與其說配置的是表和類的關係還不如說是對sql語句的關係的配置

參數是BOOK對象，與BOOK類創建了聯繫經過強大的#{}讓字段名與類屬性相關聯，實現數據的填充！

 

不得不說，java的封裝就是強！

類屬性與表字段之間聯繫的肯定，實現了對象和表中數據的關聯！

 

我的看法，望廣大網友指正！