2023最新IDEA版本Java零基础教程，赵姗姗老师带你7天入门Java架构师！

【【马士兵教育】2023最新IDEA版本Java零基础教程，赵姗姗老师带你7天入门Java架构师！】https://www.bilibili.com/video/BV1v24y1H74t?vd_source=d4c8a130bd8760e7e8cdd48d80abd00c

XML讲解

<?xml version="1.0" encoding="utf-8" ?>
<!--
version:版本号
encoding:编码格式
-->
<students>
    <student id="1">
        <name>ZhangSan</name>
        <age>18</age>
        <sex>男</sex>
        <score>89.5</score>
    </student>
    <student id="2">
        <name>LuLu</name>
        <age>19</age>
        <sex>女</sex>
        <score>95.5</score>
    </student>
    <student id="3">
        <name>MingMing</name>
        <age>17</age>
        <sex>女</sex>
        <score>80</score>
    </student>
</students>

package com.liweixiao.test17;

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.File;
import java.util.Iterator;
import java.util.List;

/**
 * @author:LiWeixiao
 * @date:2023/7/12
 * @description:
 */
public class Test {
    public static void main(String[] args) throws DocumentException {

        SAXReader sr = new SAXReader();
        Document dom = sr.read(new File("E:\\hw\\IdeaProjects\\TestBiliPro\\TestFirstModule\\src\\students.xml"));
        System.out.println(dom);

        Element studentsEle = dom.getRootElement();
        Iterator<Element> it1 = studentsEle.elementIterator();

        while (it1.hasNext()){
            Element studentEle = it1.next();
            List<Attribute> atts = studentEle.attributes();
            for(Attribute a:atts){
                System.out.println("该子节点的属性："+a.getName()+"---"+a.getText());
            }

            Iterator<Element> it2 = studentEle.elementIterator();
            while (it2.hasNext()){
                Element eles = it2.next();
                System.out.println("节点："+eles.getName()+"---"+eles.getText());
            }
            System.out.println();
        }

    }
}

JDBC

1.加载驱动
2.获取数据库连接Connection
3.创建会话-SQL命令发送器（Statement）
4.通过Statement发送SQL命令并得到结果
5.处理结果
6.关闭数据库资源（ResultSet、Statement、Connection）

createStatement不安全，prepareStatement安全。
executeUpdate增删改操作，executeQuery查询操作。

package com.liweixiao.test01;

import java.sql.*;

/**
 * @author:LiWeixiao
 * @date:2023/7/12
 * @description:
 */
public class Test {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {

        Class.forName("com.mysql.jdbc.Driver");

        String url="jdbc:mysql://localhost:3306/book?useUnicode=true&characterEncoding=utf8&useSSL=true";
        String userName="root";
        String pwd="123456";
        Connection conn = DriverManager.getConnection(url, userName, pwd);

        Statement sta = conn.createStatement();

        //int i = sta.executeUpdate("INSERT INTO t_book(id,NAME,author,price) VALUES (3,'C++','王五',50)");
        int i = sta.executeUpdate("delete from t_book where id=3");

        System.out.println(i);
        if(i>0){
            System.out.println("更新成功");
        }else {
            System.out.println("更新失败");
        }

        ResultSet rs = sta.executeQuery("select * from t_book where price < 90");
        while (rs.next()){
            System.out.println(rs.getInt("id"));
            System.out.println(rs.getString("name"));
            System.out.println(rs.getString("author"));
            System.out.println(rs.getDouble("price"));
            System.out.println();
        }

        sta.close();
        conn.close();
    }
}

MyBatis

1.创建数据库表
2.创建Maven项目
3.添加依赖
4.创建MyBatis全局配置文件
5.创建实体类
6.创建映射文件
7.编写测试类，启动项目

sqlSession，查询不用commit，增删改需要commit

【一、maven的pom】
pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.liweixiao</groupId>
    <artifactId>TestMyBatis02</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!--mysql驱动的依赖-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <!--mybatis驱动的依赖-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.9</version>
        </dependency>
        <!--log4j驱动的依赖-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>

</project>

【二、resources】
db.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/book?useUnicode=true&characterEncoding=utf-8&useSSL=true
username=root
password=123456

log4j.properties

# Log4j中定义的级别
log4j.rootLogger=error, stdout

# 命名空间
log4j.logger.com.liweixiao.mapper.BookMapper=error

# console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

mybatis.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>
    <properties resource="db.properties"></properties>
    <typeAliases>
        <package name="com.liweixiao.pojo"/>
    </typeAliases>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com/liweixiao/mapper/BookMapper.xml"/>
    </mappers>
</configuration>

BookMapper.xml
com/liweixiao/mapper/BookMapper.xml要一级一级新建文件夹

<?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.liweixiao.mapper.BookMapper">
    <select id="selectAllBooks" resultType="Book">
        select * from t_book
    </select>
    <select id="selectOneBook" resultType="Book">
        select * from t_book where name = #{arg0} and author = #{arg1}
    </select>
    <select id="selectOneBook2" resultType="Book">
        select * from t_book where name = #{name} and author = #{author}
    </select>
    <select id="selectOneBook3" resultType="Book">
        select * from t_book where name = #{arg0} and author = #{arg1.author}
    </select>

    <insert id="addOneBook">
        insert into t_book(id,name,author,price) values (#{id},#{name},#{author},#{price})
    </insert>

    <delete id="deleteOneBook">
        delete from t_book where id = #{id}
    </delete>

    <update id="updateOneBook">
        update t_book set price=price/2 where id = #{id}
    </update>
</mapper>

【三、java】
Book.java

package com.liweixiao.pojo;

/**
 * @author:LiWeixiao
 * @date:2023/7/13
 * @description:搭建第一个MyBatis框架
 */
public class Book {

    private int id;
    private String name;
    private String author;
    private double price;

    public int getId() {
        return id;
    }

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

    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;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public Book() {
    }

    public Book(int id, String name, String author, double price) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.price = price;
    }

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

BookMapper.java

package com.liweixiao.mapper;

import com.liweixiao.pojo.Book;

import java.util.List;

/**
 * @author:LiWeixiao
 * @date:2023/7/13
 * @description:
 */
public interface BookMapper {
    //查询
    /*public abstract */List selectAllBooks();
    public abstract Book selectOneBook(String name, String author);
    public abstract Book selectOneBook2(Book book);
    public abstract Book selectOneBook3(String name,Book book);

    //新增
    public abstract int addOneBook(Book book);

    //删除
    public abstract int deleteOneBook(int id);

    //修改
    public abstract int updateOneBook(int id);

}

【四、test】
Test.java

package com.liweixiao.test;

import com.liweixiao.mapper.BookMapper;
import com.liweixiao.pojo.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 java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**
 * @author:LiWeixiao
 * @date:2023/7/13
 * @description:
 */
public class Test {
    public static void main(String[] args) throws IOException {
        //指定核心配置文件的路径
        String resource = "mybatis.xml";
        //获取加载配置文件的输入流
        InputStream inputStream = Resources.getResourceAsStream(resource);
        //加载配置文件
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //通过工厂类获取一个会话
        SqlSession sqlSession = sqlSessionFactory.openSession();

        //动态代理模式？BookMapper mapper = BookMapper实现类，多态的一种方式
        BookMapper mapper = sqlSession.getMapper(BookMapper.class);
        List list = mapper.selectAllBooks();
        for (int i = 0; i < list.size(); i++) {
            Book b = (Book) (list.get(i));
            System.out.println(b);
        }

        sqlSession.close();
    }
}

/*Book book = mapper.selectOneBook("Python", "李四");*/
Book b2 = new Book();
b2.setName("Python");
b2.setAuthor("李四");
/*Book book = mapper.selectOneBook2(b2);*/
Book book= mapper.selectOneBook3("Python", b2);

System.out.println(book);

Book b = new Book(4, "go", "赵六", 18.8);
int i = mapper.addOneBook(b);
if(i>0){
    System.out.println("新增一条");
}else {
    System.out.println("新增失败");
}
//事务相关的操作
sqlSession.commit();

int i = mapper.deleteOneBook(4);
if(i>0){
    System.out.println("删除成功");
}else {
    System.out.println("删除失败");
}
sqlSession.commit();

int i = mapper.updateOneBook(2);
if(i>0){
    System.out.println("更新成功");
}else {
    System.out.println("更新失败");
}
sqlSession.commit();

Spring

IOC控制反转，也被称为DI依赖注入。

【一、maven的pom】
pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.liweixiao</groupId>
    <artifactId>TestSpring01</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.3.23</version>
        </dependency>
    </dependencies>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

</project>

【二、resources】
applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <!--属性的设值注入-->
    <bean id="b" class="com.liweixiao.pojo.Book">
        <property name="id" value="1"></property>
        <property name="name" value="Java"></property>
    </bean>
    <!--属性的构造注入-->
    <bean id="b2" class="com.liweixiao.pojo.Book">
        <constructor-arg name="id" value="2"></constructor-arg>
        <constructor-arg name="name" value="Python"></constructor-arg>
    </bean>
    <!--<bean id="boy" class="com.liweixiao.pojo.Boy">
        <property name="age" value="20"></property>
        <property name="name" value="小强"></property>
    </bean>
    <bean id="girl" class="com.liweixiao.pojo.Girl">
        <property name="age" value="19"></property>
        <property name="name" value="露露"></property>
        <property name="boyfriend" ref="boy"></property>
    </bean>
    <bean id="boy2" class="com.liweixiao.pojo.Boy">
        <constructor-arg name="age" value="23"></constructor-arg>
        <constructor-arg name="name" value="小明"></constructor-arg>
    </bean>
    <bean id="girl2" class="com.liweixiao.pojo.Girl">
        <constructor-arg name="age" value="21"></constructor-arg>
        <constructor-arg name="name" value="喵喵"></constructor-arg>
        <constructor-arg name="boyfriend" ref="boy2"></constructor-arg>
    </bean>-->
</beans>

【三、java】
Book.java

package com.liweixiao.pojo;

/**
 * @author:LiWeixiao
 * @date:2023/7/14
 * @description:
 */
public class Book {
    private int id;
    private String name;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        System.out.println("id的setter方法");
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        System.out.println("name的setter方法");
        this.name = name;
    }

    public Book() {
        System.out.println("Book类的空构造器");
    }

    public Book(int id, String name) {
        System.out.println("Book类的有参构造器");
        this.id = id;
        this.name = name;
    }

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

【四、test】
Test.java

package com.liweixiao.test;

import com.liweixiao.pojo.Book;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * @author:LiWeixiao
 * @date:2023/7/14
 * @description:
 */
public class Test {
    public static void main(String[] args) {
        //创建Spring容器
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        //获取对象
        Book b = (Book) (context.getBean("b"));
        System.out.println(b);
        Book b2 = (Book) (context.getBean("b2"));
        System.out.println(b2);

        //获取对象
        /*Girl g = (Girl) (context.getBean("girl"));*/
        /*Girl g = (Girl) (context.getBean("girl2"));
        System.out.println(g);*/
        Girl g = (Girl) (context.getBean("girl"));
        System.out.println(g);
        Boy b = (Boy) (context.getBean("boy"));
        System.out.println(b);
    }
}

【补充：注解的使用】

applicationContext.xml中添加

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.liweixiao.pojo"></context:component-scan>
</beans>

Girl.java

package com.liweixiao.pojo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
public class Girl {
    @Value("18")
    private int age;
    @Value("莎莎")
    private String name;
    @Autowired
    private Boy boyfriend;

Boy.java

package com.liweixiao.pojo;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
public class Boy {
    @Value("22")
    private int age;
    @Value("小壮")
    private String name;

}

SpringMVC

【一、maven的pom】
新建webapp项目
pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.liweixiao</groupId>
  <artifactId>TestSpringMVC</artifactId>
  <packaging>war</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>TestSpringMVC Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <dependencies>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.3.23</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.2</version>
        <configuration>
          <path>/TestSpringMVC</path>
          <port>8080</port>
        </configuration>
      </plugin>
    </plugins>
    <finalName>TestSpringMVC</finalName>
  </build>
</project>

【二、resources】
springmvc.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--扫描包-->
    <context:component-scan base-package="com.liweixiao.controller"></context:component-scan>
    <!--让注解@RequestMapping生效-->
    <mvc:annotation-driven></mvc:annotation-driven>

</beans>

【三、java】
TestController.java

package com.liweixiao.controller;

import com.liweixiao.pojo.Person;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author:LiWeixiao
 * @date:2023/7/17
 * @description:控制器类
 */

@Controller
public class TestController {
    @RequestMapping("/test1")
    public String test1(){
        return "index.jsp";
    }

    @RequestMapping("/testParam")
    public String testParam(String name,int age){
        System.out.println(name+"---"+age);
        return "index1.jsp";
    }

    @RequestMapping("/testParam2")
    public String testParam2(Person person){
        System.out.println(person);
        return "index1.jsp";
    }
}

Person.java，包含name、age等属性

【四、webapp】
web.xml，程序的入口

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                      http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

index.jsp

案例SSM书城

【一、maven的pom】
新建webapp项目
pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.liweixiao</groupId>
  <artifactId>TestSSM</artifactId>
  <packaging>war</packaging>
  <version>1.0-SNAPSHOT</version>

  <dependencies>
    <!--1、mybatis驱动的依赖-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.9</version>
    </dependency>
    <!--2、mysql驱动的依赖-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.47</version>
    </dependency>
    <!--3、log4j驱动的依赖-->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>
    <!--4、spring核心依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.3.23</version>
    </dependency>
    <!--5、springjdbc依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.3.24</version>
    </dependency>
    <!--6、spring整合mybatis依赖-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>2.0.2</version>
    </dependency>
    <!--7、springMVC依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.3.23</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <!--加入tomcat7插件-->
      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.2</version>
        <configuration>
          <path>/testssm</path>
          <port>8080</port>
        </configuration>
      </plugin>
    </plugins>
  </build>

</project>

【二、resources】
applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">

    <!--1、连接数据库，获取数据源-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <!--属性的设值注入-->
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/book?useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=true"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
    </bean>
    <!--2、获取SqlSessionFactory对象-->
    <bean id="factory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!--注入数据源-->
        <property name="dataSource" ref="dataSource"/>
        <!--给包下类起别名-->
        <property name="typeAliasesPackage" value="com.liweixiao.pojo"/>
        <!--解析mybatis.xml-->
        <property name="configLocation" value="classpath:mybatis.xml"/>
    </bean>
    <!--3、扫描mapper文件-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="sqlSessionFactoryBeanName" value="factory"></property>
        <property name="basePackage" value="com.liweixiao.mapper"></property>
    </bean>
    <!--4、扫描包下注解-->
    <context:component-scan base-package="com.liweixiao.serviceImpl"></context:component-scan>
</beans>

springmvc.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--扫描包-->
    <context:component-scan base-package="com.liweixiao.controller"></context:component-scan>
    <!--让注解@RequestMapping生效-->
    <mvc:annotation-driven></mvc:annotation-driven>

</beans>

log4j.properties见上文
mybatis.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>
    <settings>
        <setting name="logImpl" value="LOG4J"/>
    </settings>
</configuration>

BookMapper.xml
com/liweixiao/mapper/BookMapper.xml要一级一级新建文件夹

<?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.liweixiao.mapper.BookMapper">
    <select id="selectAll" resultType="book">
        select * from t_book
    </select>
</mapper>

【三、java】
com.liweixiao.pojo.Book.java见上文
com.liweixiao.mapper.BookMapper.java

package com.liweixiao.mapper;

import java.util.List;

/**
 * @author:LiWeixiao
 * @date:2023/7/18
 * @description:
 */
public interface BookMapper {
    List selectAll();
}

com.liweixiao.service.BookService.java

package com.liweixiao.service;

import java.util.List;

/**
 * @author:LiWeixiao
 * @date:2023/7/18
 * @description:
 */
public interface BookService {
    List findAll();
}

com.liweixiao.serviceImpl.BookServiceImpl.java

package com.liweixiao.serviceImpl;

import com.liweixiao.mapper.BookMapper;
import com.liweixiao.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * @author:LiWeixiao
 * @date:2023/7/18
 * @description:
 */
@Service
public class BookServiceImpl implements BookService {
    @Autowired
    private BookMapper bookMapper;

    public List findAll() {
        return bookMapper.selectAll();
    }
}

com.liweixiao.controller.BookController.java

package com.liweixiao.controller;

import com.liweixiao.pojo.Book;
import com.liweixiao.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.List;

/**
 * @author:LiWeixiao
 * @date:2023/7/18
 * @description:
 */
@Controller
public class BookController {
    @Autowired
    private BookService bookService;

    @RequestMapping(value = "/findAllBooks",produces = "text/html;charset=utf-8")
    /*tomcat8以上支持ResponseBody*/
    @ResponseBody
    public String findAll(){
        List list = bookService.findAll();
        System.out.println("一共有几本书籍："+list.size());
        String books="";
        for (int i = 0; i < list.size(); i++) {
            Book book = (Book) (list.get(i));
            books += book.getId();
            books += book.getName();
            books += book.getPrice();
        }
        return books;
    }
}

【四、webapp】
web.xml，程序的入口

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                      http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

  <servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

  <!--监听器监听-->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>

</web-app>

SpringBoot案例书城

【1、maven的pom】
pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.liweixiao</groupId>
    <artifactId>TestSpringBoot</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>2.7.6</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.7.6</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.3</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
    </dependencies>

</project>

【2、resource】
application.yml

server:
  port: 8888
  servlet:
    context-path: /springbootssm
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/book?useUnicode=true&characterEncoding=utf-8&useSSL=true
    driver-class-name: com.mysql.jdbc.Driver
    username: root
    password: 123456
mybatis:
  type-aliases-package: com.liweixiao.pojo
  mapper-location: classpath:com/liweixiao/mapper/*.xml

BookMapper.xml
com/liweixiao/mapper/BookMapper.xml要一级一级新建文件夹

<?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.liweixiao.mapper.BookMapper">
    <select id="selectAllBooks" resultType="book">
        select * from t_book
    </select>
</mapper>

【3、java】
com.liweixiao.pojo.Book.java见上文
com.liweixiao.mapper.BookMapper.java

package com.liweixiao.mapper;

import java.util.List;

/**
 * @author:LiWeixiao
 * @date:2023/7/19
 * @description:
 */
public interface BookMapper {

    List selectAllBooks();
}

com.liweixiao.service.BookService.java

package com.liweixiao.service;

import java.util.List;

/**
 * @author:LiWeixiao
 * @date:2023/7/19
 * @description:
 */
public interface BookService {
    List findAllBooks();
}

com.liweixiao.service.impl.BookServiceImpl.java

package com.liweixiao.service.impl;

import com.liweixiao.mapper.BookMapper;
import com.liweixiao.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * @author:LiWeixiao
 * @date:2023/7/19
 * @description:
 */
@Service
public class BookServiceImpl implements BookService {
    @Autowired
    private BookMapper bookMapper;

    public List findAllBooks() {
        return bookMapper.selectAllBooks();
    }
}

com.liweixiao.controller.BookController.java

package com.liweixiao.controller;

import com.liweixiao.pojo.Book;
import com.liweixiao.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.List;

/**
 * @author:LiWeixiao
 * @date:2023/7/19
 * @description:
 */
@Controller
public class BookController {
    @Autowired
    private BookService bookService;

    @RequestMapping("/findBooks")
//    @RequestMapping(value = "/findBooks",produces = "text/html;charset=utf-8")
    @ResponseBody
    public String findBooks(){
        List list = bookService.findAllBooks();
        String s="";
        for (int i = 0; i < list.size(); i++) {
            Book book = (Book) (list.get(i));
            s += book.getName();
            s += book.getPrice();
        }
        return s;
    }
}

【4、程序入口】
com.liweixiao.TestSpringBootApplication.java

package com.liweixiao;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * @author:LiWeixiao
 * @date:2023/7/19
 * @description:
 */
@SpringBootApplication
@MapperScan("com.liweixiao.mapper")
public class TestSpringBootApplication {
    public static void main(String[] args) {
        SpringApplication.run(TestSpringBootApplication.class,args);
    }
}