SSM框架整合自我总结（参考狂神说）

创建一个存放书籍的数据库表：

CREATE DATABASE `ssmbuild`;

USE `ssmbuild`;

DROP TABLE IF EXISTS `books`;

CREATE TABLE `books`(
`bookID` INT(10) NOT NULL AUTO_INCREMENT COMMENT '书id',
`bookName` VARCHAR(100) NOT NULL COMMENT '书名',
`bookCounts` INT(11) NOT NULL COMMENT '数量',
`detail` VARCHAR(200) NOT NULL COMMENT '描述',
KEY `bookID` (`bookID`)


)ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT  INTO `books`(`bookID`,`bookName`,`bookCounts`,`detail`)VALUES
(1,'Java',1,'从入门到放弃'),
(2,'MySQL',10,'从删库到跑路'),
(3,'Linux',5,'从进门到进牢');

新建一个maven项目，添加web支持，第一步先导jar包：junit、数据库、数据库连接池、servlet、mybatis、spring相关jar包和maven资源过滤支持：

   <!--junit、数据库驱动、数据库连接池、servlet、mybatis、、spring-->
    <dependencies>
        <!--Junit-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <!--数据库驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <!-- 数据库连接池 -->
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.5.2</version>
        </dependency>

        <!--Servlet - JSP -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <!--Mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.2</version>
        </dependency>

        <!--Spring-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.20</version>
        </dependency>
        <!--json依赖-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.13.1</version>
        </dependency>
    </dependencies>

    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties
                    **/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties
                    **/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>

点击项目结构，点击Artifacts在WEB-INF下新建一个lib，将依赖导入进去，然后在src/main/java下创建四层同级的包：service层、controller层、pojo层、dao层，路径为com.cjh.service…在idea中连接数据库，现在先在resources资源下新建一个database.properties文件用于存放mysql的相关信息：

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/ssmbuild?useSSL=false&useUnicode=true&characterEncoding=utf8
user=root
password=123456

这里有两个注意点可能会报错：mysql8.0+的需要在url中添加时区设置&serverTimezone=UTC，还有user不能换成username不然也会报错

在resources资源下新建一个mybatis-config.xml文件用来设置mybatis的配置文件：

<?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>

    <typeAliases>
        <package name="com.cjh.pojo"/>

    </typeAliases>
    <mappers>
        <mapper class="com.cjh.dao.BookMapper"/>

    </mappers>


</configuration>

接下来在pojo包下创建一个实体类用lombok注释：

package com.cjh.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Books {
    private int bookID;
    private String bookName;
    private int bookCounts;
    private String detail;
  
}

接下来在dao层创建一个BookMapper接口：

package com.cjh.dao;

import com.cjh.pojo.Books;
import org.apache.ibatis.annotations.Param;



import java.util.*;

public interface BookMapper {
    //增加一本书
    int addBook(Books book);

    //删除一本书
    int deleteBookById(@Param("bookId") int id);
    
    //更改一本书
    int updateBook(Books book);
    
    //查询一本书
    Books queryBookById(@Param("bookId")int id);
    
    //查询所有的熟
    List<Books> queryAllBook();


}

编写对应接口的Mapper.xml文件，需要导入Mybatis的包：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.cjh.dao.BookMapper">
    <insert id="addBook" parameterType="books">
        insert into ssmbuild.books (bookName, bookCounts, detail)
        values (#{bookName},#{bookCounts},#{detail});

    </insert>

    <delete id="deleteBookById" parameterType="int">
        DELETE FROM ssmbuild.books WHERE bookID=#{bookId};

    </delete>

    <update id="updateBook" parameterType="books">
        update ssmbuild.books set bookName = #{bookName},
         bookName = #{bookName},
         bookCounts = #{bookCounts},
         detail = #{detail}
      where bookID = #{bookID};
        
    </update>

    <select id="queryBookById" parameterType="int" resultType="books">
        SELECT * FROM ssmbuild.books WHERE bookID=#{bookId};
        
    </select>
    
    <select id="queryAllBook" parameterType="books">
        SELECT * FROM ssmbuild.books;
        
        
    </select>


</mapper>

在service层创建一个BookService接口和实现类：

package com.cjh.service;

import com.cjh.pojo.Books;

import java.util.List;

public interface BookService {
    
    //增加一本书
    int addBook(Books book);

    //删除一本书
    int deleteBookById( int id);

    //更改一本书
    int updateBook(Books book);

    //查询一本书
    Books queryBookById(int id);

    //查询所有的熟
    List<Books> queryAllBook();
    
}

package com.cjh.service;

import com.cjh.dao.BookMapper;
import com.cjh.pojo.Books;

import java.util.List;
public class BookServiceImpl implements BookService{

    private BookMapper bookMapper;

    public void setBookMapper(BookMapper bookMapper) {
        this.bookMapper = bookMapper;
    }

    @Override
    public int addBook(Books book) {
        return bookMapper.addBook(book);
    }

    @Override
    public int deleteBookById(int id) {
        return bookMapper.deleteBookById(id);
    }

    @Override
    public int updateBook(Books book) {
        return bookMapper.updateBook(book);
    }

    @Override
    public Books queryBookById(int id) {
        return bookMapper.queryBookById(id);
    }

    @Override
    public List<Books> queryAllBook() {
        return bookMapper.queryAllBook();
    }
}

到这里底层的需求已经编写完毕。

下面开始整合mybatis和spring,我们这里数据源使用c3p0连接池；
我们去编写Spring整合Mybatis的相关的配置文件；spring-dao.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
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       https://www.springframework.org/schema/context/spring-context.xsd">

    <!--1.关联数据库文件-->
    <context:property-placeholder location="classpath:database.properties"/>

    <!--2.绑定源数据-->
    <!--3.连接数据库-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${driver}"/>
        <property name="jdbcUrl" value="${url}"/>
        <property name="user" value="${user}"/>
        <property name="password" value="${password}"/>
        <!-- c3p0连接池的私有属性 -->
        <property name="maxPoolSize" value="30"/>
        <property name="minPoolSize" value="10"/>
        <!-- 关闭连接后不自动commit -->
        <property name="autoCommitOnClose" value="false"/>
        <!-- 获取连接超时时间 -->
        <property name="checkoutTimeout" value="10000"/>
        <!-- 当获取连接失败重试次数 -->
        <property name="acquireRetryAttempts" value="2"/>
    </bean>
    <!--4.创建sqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
    </bean>

    <!-- 4.配置扫描Dao接口包，动态实现Dao接口注入到spring容器中 -->
    <!--解释 ：https://www.cnblogs.com/jpfss/p/7799806.html-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 注入sqlSessionFactory -->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <!-- 给出需要扫描Dao接口包 -->
        <property name="basePackage" value="com.cjh.dao"/>
    </bean>

</beans>

配置spring-service.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:tx="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       https://www.springframework.org/schema/context/spring-context.xsd">

   <!--1.扫描service相关的bean-->
    <tx:component-scan base-package="com.cjh.service"/>

    <!--2.将BookServiceImpl注入到spring容器中-->
    <bean id="bookServiceImpl" class="com.cjh.service.BookServiceImpl">
        <property name="bookMapper" value="bookMapper"/>

    </bean>
    <!--3.配置事务管理器-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <!--注入数据库连接池-->
        <property name="dataSource" ref="dataSource"/>
    </bean>

</beans>

这里可能出现bookMapper或者是dataSource爆红查看一下spring-dao下中的路径是否正确

这个时候我们只剩下springmvc没有配置了
在web.xml中：

<?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_3_1.xsd"
         version="3.1">

    <!--DispatcherServlet-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <!--这里要注意是加载总的配置文件-->
            <param-value>classpath:applicationContext.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>
    <!--encodingFilter解决乱码问题-->
    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <url-pattern>/*
    
    
    
        15
    

spring-mvc.xml配置：

<?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
       http://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
       http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 配置SpringMVC -->
    <!-- 1.开启SpringMVC注解驱动 -->
    <!-- 防止json乱码问题 -->
    <mvc:annotation-driven>
    <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                        <property name="failOnEmptyBeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>
    <!--静态资源默认servlet配置-->
    <mvc:default-servlet-handler/>

    <!--配置视图解析器-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
    <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
    <!--前缀-->
    <property name="prefix" value="/WEB-INF/jsp/"/>
    <!--后缀-->
    <property name="suffix" value=".jsp"/>

</bean>
    <!--扫描controller层相关的bean-->
   <context:component-scan base-package="com.cjh.controller"/>


</beans>

applicationContext总配置文件下：

<?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:tx="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       https://www.springframework.org/schema/context/spring-context.xsd">

    <import resource="classpath:spring-mvc.xml"/>
    <import resource="classpath:spring-service.xml"/>
    <import resource="classpath:spring-dao.xml"/>
    
</beans>

到这里我们就已经把所有的配置文件配置好了
在WEB-INF下新建一个jsp的文件夹，接下来我们开始写controller层，在controller层新建一个类

package com.cjh.controller;

import com.cjh.pojo.Books;
import com.cjh.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.List;


@Controller
@RequestMapping("/book")
public class BookController {

    @Autowired
    private BookService bookService;

    @RequestMapping("/allBook")
    public String list(Model model){
        List<Books> list = bookService.queryAllBook();
        model.addAttribute("list",list);
        return "allBook";

    }

}

index.jsp的测试代码如下：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>首页</title>
  </head>
  <body>
 <h1>
   <a href="${pageContext.request.contextPath}/book/allBook">点击进入列表页</a>
 </h1>
  </body>
</html>

和WEB-INF/jsp下的allBook.jsp的测试代码如下：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>书籍列表</title>
</head>
<body>
    <h3>书籍列表</h3>
</body>
</html>

配置tomcat以后开始运行
出现了错误500：java.lang.IllegalStateException: Cannot convert value of type ‘java.lang.String’ to required type ‘com.cjh.dao.BookMapper’ for property ‘bookMapper’: no matching editors or conversion strategy found
经排查发现是spring-service.xml中 中的value=“bookMapper”应该为ref=“bookMapper”

如果出现bookMapper出现爆红可能是idea中的bug
重新启动后出现500错误：org.apache.ibatis.executor.ExecutorException: A query was run and no Result Maps were found for the Mapped Statement ‘com.cjh.dao.BookMapper.queryAllBook’. It’s likely that neither a Result Type nor a Result Map was specified.经排查发现是dao层下的BookMapper.xml文件中

 <select id="queryAllBook" parameterType="books">
        SELECT * FROM ssmbuild.books;


    </select>

parameterType="books"应该改为resultType=“books”
再次启动后能够正常跳转。