SSM小项目-(2)-配置整合SSM

有时配置文件会报错，主要是网络读取不到文件的原因。可以先clean project ，然后再重新update project。报错举例：

- schema_reference.4: Failed to read schema document 'http://www.springframework.org/schema/tx/spring- tx-4.3.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.

一、配置Web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	id="WebApp_ID" version="2.5">
	
	<!--1、启动Spring的容器  -->
	<!-- needed for ContextLoaderListener -->
	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>classpath:springIOC.xml</param-value>
	</context-param>

	<!-- Bootstraps the root web application context before servlet initialization -->
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
	
	<!--2、springmvc的前端控制器，拦截所有请求  -->
	<!-- The front controller of this Spring Web application, responsible for handling all application requests -->
	<servlet>
		<servlet-name>springMVC</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<load-on-startup>1</load-on-startup>
	</servlet>

	<!-- Map all requests to the DispatcherServlet for handling -->
	<servlet-mapping>
		<servlet-name>springMVC</servlet-name>
		<url-pattern>/</url-pattern>
	</servlet-mapping>
	
	<!-- 3、字符编码过滤器，一定要放在所有过滤器之前 -->
	<filter>
		<filter-name>CharacterEncodingFilter</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>
		<init-param>
			<param-name>forceRequestEncoding</param-name>
			<param-value>true</param-value>
		</init-param>
		<init-param>
			<param-name>forceResponseEncoding</param-name>
			<param-value>true</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>CharacterEncodingFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	
	<!-- 4、使用Rest风格的URI，将页面普通的post请求转为指定的delete或者put请求 -->
	<filter>
		<filter-name>HiddenHttpMethodFilter</filter-name>
		<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>HiddenHttpMethodFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
<!-- 5、直接支持put请求的拦截器，即在put请求时将请求体数据封装成map，并让springmvc能够通过request.getParameter(属性名) 来获取数据 -->
	<filter>
		<filter-name>HttpPutFormContentFilter</filter-name>
		<filter-class>org.springframework.web.filter.HttpPutFormContentFilter</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>HttpPutFormContentFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	
</web-app>

二、配置springmvc

与web.xml目录同级下创建，springMVC-servlet.xml ,这是根据web.xml中配置的springMVC 得来的。

<?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/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">

	<!--SpringMVC的配置文件，包含网站跳转逻辑的控制，配置  -->
	<context:component-scan base-package="com.ssm.crud" use-default-filters="false">
		<!--只扫描控制器。  -->
		<context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
	</context:component-scan>
	
	<!--配置视图解析器，方便页面返回  -->
	<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value="/WEB-INF/views/"></property>
		<property name="suffix" value=".jsp"></property>
	</bean>
	
	<!--两个标准配置  -->
	<!-- 将springmvc不能处理的请求交给tomcat -->
	<mvc:default-servlet-handler/>
	<!-- 能支持springmvc更高级的一些功能，JSR303校验，快捷的ajax...映射动态请求 -->
	<mvc:annotation-driven/>

</beans>

三、配置spring容器

因为web.xml已经定义了：spring的容器名是 springIOC，路径是类的根目录。
所以开发的时候，就在src/main/resources  目录下创建 springIOC.xml 配置文件。 

<?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:aop="http://www.springframework.org/schema/aop"
	xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">

	<context:component-scan base-package="com.ssm.crud">
		<context:exclude-filter type="annotation"
			expression="org.springframework.stereotype.Controller" />
	</context:component-scan>

	<!-- Spring的配置文件，这里主要配置和业务逻辑有关的 -->
	<!--=================== 数据源，事务控制，xxx ================-->
	<context:property-placeholder location="classpath:dbconfig.properties" />
	<bean id="pooledDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
		<property name="url" value="${jdbc.url}" />
		<property name="driverClassName" value="${jdbc.driver}" />
		<property name="username" value="${jdbc.user}" />
		<property name="password" value="${jdbc.password}" />
	</bean>

	<!--================== 配置和MyBatis的整合=============== -->
	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
		<!-- 指定mybatis全局配置文件的位置 -->
		<property name="configLocation" value="classpath:mybatis-config.xml"></property>
		<property name="dataSource" ref="pooledDataSource"></property>
		<!-- 指定mybatis，mapper文件的位置 -->
		<property name="mapperLocations" value="classpath:mapper/*.xml"></property>
	</bean>

	<!-- 配置扫描器，将mybatis接口的实现加入到ioc容器中 -->
	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
		<!--扫描所有dao接口的实现，加入到ioc容器中 -->
		<property name="basePackage" value="com.ssm.crud.mapper"></property>
	</bean>
	
	<!-- 配置一个可以执行批量的sqlSession -->
	<bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
		<constructor-arg name="sqlSessionFactory" ref="sqlSessionFactory"></constructor-arg>
		<constructor-arg name="executorType" value="BATCH"></constructor-arg>
	</bean>
	<!--=============================================  -->

	<!-- ===============事务控制的配置 ================-->
	<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
		<!--控制住数据源  -->
		<property name="dataSource" ref="pooledDataSource"></property>
	</bean>
	<!--开启基于注解的事务，使用xml配置形式的事务（必要主要的都是使用配置式）  -->
	<aop:config>
		<!-- 切入点表达式  固定为:execution()  
		内部参数【 *(代表返回值类型所以)  com.ssm.crud.service..(代表这个包及下面的子包)  *(紧跟前面的这个星号，代表类中的所有方法)  (..)(紧跟前面的这个标记，代表方法里面的参数 任意多)  】-->
		<aop:pointcut expression="execution(* com.ssm.crud.service..*(..))" id="txPoint"/>
		<!-- 配置事务增强  txAdvice:代表事务切入规则  txPoint:代表切入哪些方法 -->
		<aop:advisor advice-ref="txAdvice" pointcut-ref="txPoint"/>
	</aop:config>
	
	<!--配置事务增强，也就是 事务如何切入  -->
	<tx:advice id="txAdvice" transaction-manager="transactionManager">
		<tx:attributes>
			<!-- 所有方法都是事务方法 -->
			<tx:method name="*"/>
			<!--以get开始的所有方法 ，认为都是查询方法，可以调优，写成 read only = true -->
			<tx:method name="get*" read-only="true"/>
		</tx:attributes>
	</tx:advice>
	
	<!-- Spring配置文件的核心点（数据源、与mybatis的整合，事务控制） -->
	
</beans>

四、配置mybatis.xml和数据库属性文件

mybatis-config.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="mapUnderscoreToCamelCase" value="true"/>
	</settings>
	
	<typeAliases>
		<package name="com.ssm.crud.bean"/>
	</typeAliases>
	

</configuration>

dbconfig.properties

##### 	<!-- http://jingyan.baidu.com/article/b7001fe197a3f60e7282dd8d.html 中文数据库存取乱码问题 ,在 xml文件中 & 要转义成 &amp; 而到了properties中就直接用&就行了 -->
jdbc.url=jdbc:mysql://localhost:3306/ssm_crud?useUnicode=true&characterEncoding=UTF-8
jdbc.driver=com.mysql.jdbc.Driver
jdbc.user=root
jdbc.password=Cool123!

五、搭建数据库

tbl_emp

emp_id     emp_name   gender   email     d_id

tbl_dept

dept_id      dept_name

六、mybatis自动生成代码（MBG）

1、先导入mybatis-generator-core.jar 包。
在pom.xml中，添加依赖【前面已经添加好了】

<!-- MBG -->
<!-- https://mvnrepository.com/artifact/org.mybatis.generator/mybatis-generator-core -->
<dependency>
	<groupId>org.mybatis.generator</groupId>
	<artifactId>mybatis-generator-core</artifactId>
	<version>1.3.5</version>
</dependency>

2、添加 mbg.xml 配置文件

特别提醒：下面的路径写错的话，MBG 就会无法生成，虽然 运行没有报错。

linux系统下：  targetProject=”./src/main/java”
Windows系统下：targetProject=”.\src\main\java”

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
  PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
  "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>

	<context id="DB2Tables" targetRuntime="MyBatis3">
		<commentGenerator>
			<property name="suppressAllComments" value="true" />
		</commentGenerator>
		<!-- 配置数据库连接 -->
		<jdbcConnection 
		    driverClass="com.mysql.jdbc.Driver"
			connectionURL="jdbc:mysql://localhost:3306/ssm_crud" 
			userId="root"
			password="Cool123!">
		</jdbcConnection>

		<javaTypeResolver>
			<property name="forceBigDecimals" value="false" />
		</javaTypeResolver>

		<!-- 指定javaBean生成的位置 -->
		<javaModelGenerator 
		    targetPackage="com.ssm.crud.bean"
			targetProject="./src/main/java">
			<property name="enableSubPackages" value="true" />
			<property name="trimStrings" value="true" />
		</javaModelGenerator>

		<!--指定sql映射文件生成的位置 -->
		<sqlMapGenerator 
	    	targetPackage="mapper" 
		    targetProject="./src/main/resources">
			<property name="enableSubPackages" value="true" />
		</sqlMapGenerator>

		<!-- 指定dao接口生成的位置，mapper接口 -->
		<javaClientGenerator 
		    type="XMLMAPPER"
			targetPackage="com.ssm.crud.mapper" 
			targetProject="./src/main/java">
			<property name="enableSubPackages" value="true" />
		</javaClientGenerator>


		<!-- table指定每个表的生成策略 -->
		<table tableName="tbl_emp" domainObjectName="Employee"></table>
		<table tableName="tbl_dept" domainObjectName="Department"></table>
	</context>
</generatorConfiguration>

3、执行生成代码

package com.ssm.crud.test;

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

import org.mybatis.generator.api.MyBatisGenerator;
import org.mybatis.generator.config.Configuration;
import org.mybatis.generator.config.xml.ConfigurationParser;
import org.mybatis.generator.internal.DefaultShellCallback;

public class MBGTest {

	public static void main(String[] args) throws Exception {
		List<String> warnings = new ArrayList<String>();
		boolean overwrite = true;
		File configFile = new File("mbg.xml");
		ConfigurationParser cp = new ConfigurationParser(warnings);
		Configuration config = cp.parseConfiguration(configFile);
		DefaultShellCallback callback = new DefaultShellCallback(overwrite);
		MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config,
				callback, warnings);
		myBatisGenerator.generate(null);
		System.out.println("hhh");
	}
}

七、修改mybatis的生成文件实现关联查询

目的是使：查询employee时，能够顺便获取到 department。

1、修改bean

Employee.java

package com.ssm.crud.bean;

public class Employee {
    private Integer empId;

    private String empName;

    private String gender;

    private String email;

    private Integer dId;

    public Integer getEmpId() {
        return empId;
    }

    public void setEmpId(Integer empId) {
        this.empId = empId;
    }

    public String getEmpName() {
        return empName;
    }

    public void setEmpName(String empName) {
        this.empName = empName == null ? null : empName.trim();
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender == null ? null : gender.trim();
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email == null ? null : email.trim();
    }

    public Integer getdId() {
        return dId;
    }

    public void setdId(Integer dId) {
        this.dId = dId;
    }
    
    //添加 Department 属性，用于关联查询
    private Department department;

	public Department getDepartment() {
		return department;
	}

	public void setDepartment(Department department) {
		this.department = department;
	}


	//生成自定义构造器 ，顺便 附带 无参构造器
	public Employee(Integer empId, String empName, String gender, String email, Integer dId) {
		super();
		this.empId = empId;
		this.empName = empName;
		this.gender = gender;
		this.email = email;
		this.dId = dId;
	}

	public Employee() {
		super();
	}
	
	
}

Department.java

package com.ssm.crud.bean;

public class Department {
    private Integer deptId;

    private String deptName;

    public Integer getDeptId() {
        return deptId;
    }

    public void setDeptId(Integer deptId) {
        this.deptId = deptId;
    }

    public String getDeptName() {
        return deptName;
    }

    public void setDeptName(String deptName) {
        this.deptName = deptName == null ? null : deptName.trim();
    }

    
    //创建构造器时，一定要带上 无参构造器，出于mybatis的 赋值原因
	public Department(Integer deptId, String deptName) {
		super();
		this.deptId = deptId;
		this.deptName = deptName;
	}
    
    public Department(){
    	
    }
}

2、修改Dao接口文件

package com.ssm.crud.mapper;

import com.ssm.crud.bean.Employee;
import com.ssm.crud.bean.EmployeeExample;
import java.util.List;
import org.apache.ibatis.annotations.Param;

public interface EmployeeMapper {
    long countByExample(EmployeeExample example);

    int deleteByExample(EmployeeExample example);

    int deleteByPrimaryKey(Integer empId);

    int insert(Employee record);

    int insertSelective(Employee record);

    List<Employee> selectByExample(EmployeeExample example);

    Employee selectByPrimaryKey(Integer empId);

    int updateByExampleSelective(@Param("record") Employee record, @Param("example") EmployeeExample example);

    int updateByExample(@Param("record") Employee record, @Param("example") EmployeeExample example);

    int updateByPrimaryKeySelective(Employee record);

    int updateByPrimaryKey(Employee record);
    
    
    // 为了 提供 关联查询，自己添加的 两个接口 方法
    List<Employee> selectByExampleWithDept(EmployeeExample example);
    Employee selectByPrimaryKeyWithDept(Integer empId);
}

3、修改sql映射文件

<?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.ssm.crud.mapper.EmployeeMapper">
  <resultMap id="BaseResultMap" type="com.ssm.crud.bean.Employee">
    <id column="emp_id" jdbcType="INTEGER" property="empId" />
    <result column="emp_name" jdbcType="VARCHAR" property="empName" />
    <result column="gender" jdbcType="CHAR" property="gender" />
    <result column="email" jdbcType="VARCHAR" property="email" />
    <result column="d_id" jdbcType="INTEGER" property="dId" />
  </resultMap>
  <sql id="Example_Where_Clause">
    <where>
      <foreach collection="oredCriteria" item="criteria" separator="or">
        <if test="criteria.valid">
          <trim prefix="(" prefixOverrides="and" suffix=")">
            <foreach collection="criteria.criteria" item="criterion">
              <choose>
                <when test="criterion.noValue">
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue">
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue">
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue">
                  and ${criterion.condition}
                  <foreach close=")" collection="criterion.value" item="listItem" open="(" separator=",">
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Update_By_Example_Where_Clause">
    <where>
      <foreach collection="example.oredCriteria" item="criteria" separator="or">
        <if test="criteria.valid">
          <trim prefix="(" prefixOverrides="and" suffix=")">
            <foreach collection="criteria.criteria" item="criterion">
              <choose>
                <when test="criterion.noValue">
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue">
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue">
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue">
                  and ${criterion.condition}
                  <foreach close=")" collection="criterion.value" item="listItem" open="(" separator=",">
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Base_Column_List">
    emp_id, emp_name, gender, email, d_id
  </sql>
  
  <!-- 自动创建的是 查询员工不带部门信息的 -->
  <select id="selectByExample" parameterType="com.ssm.crud.bean.EmployeeExample" resultMap="BaseResultMap">
    select
    <if test="distinct">
      distinct
    </if>
    <include refid="Base_Column_List" />
    from tbl_emp
    <if test="_parameter != null">
      <include refid="Example_Where_Clause" />
    </if>
    <if test="orderByClause != null">
      order by ${orderByClause}
    </if>
  </select>
  <select id="selectByPrimaryKey" parameterType="java.lang.Integer" resultMap="BaseResultMap">
    select 
    <include refid="Base_Column_List" />
    from tbl_emp
    where emp_id = #{empId,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer">
    delete from tbl_emp
    where emp_id = #{empId,jdbcType=INTEGER}
  </delete>
  <delete id="deleteByExample" parameterType="com.ssm.crud.bean.EmployeeExample">
    delete from tbl_emp
    <if test="_parameter != null">
      <include refid="Example_Where_Clause" />
    </if>
  </delete>
  <insert id="insert" parameterType="com.ssm.crud.bean.Employee">
    insert into tbl_emp (emp_id, emp_name, gender, 
      email, d_id)
    values (#{empId,jdbcType=INTEGER}, #{empName,jdbcType=VARCHAR}, #{gender,jdbcType=CHAR}, 
      #{email,jdbcType=VARCHAR}, #{dId,jdbcType=INTEGER})
  </insert>
  <insert id="insertSelective" parameterType="com.ssm.crud.bean.Employee">
    insert into tbl_emp
    <trim prefix="(" suffix=")" suffixOverrides=",">
      <if test="empId != null">
        emp_id,
      </if>
      <if test="empName != null">
        emp_name,
      </if>
      <if test="gender != null">
        gender,
      </if>
      <if test="email != null">
        email,
      </if>
      <if test="dId != null">
        d_id,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides=",">
      <if test="empId != null">
        #{empId,jdbcType=INTEGER},
      </if>
      <if test="empName != null">
        #{empName,jdbcType=VARCHAR},
      </if>
      <if test="gender != null">
        #{gender,jdbcType=CHAR},
      </if>
      <if test="email != null">
        #{email,jdbcType=VARCHAR},
      </if>
      <if test="dId != null">
        #{dId,jdbcType=INTEGER},
      </if>
    </trim>
  </insert>
  <select id="countByExample" parameterType="com.ssm.crud.bean.EmployeeExample" resultType="java.lang.Long">
    select count(*) from tbl_emp
    <if test="_parameter != null">
      <include refid="Example_Where_Clause" />
    </if>
  </select>
  <update id="updateByExampleSelective" parameterType="map">
    update tbl_emp
    <set>
      <if test="record.empId != null">
        emp_id = #{record.empId,jdbcType=INTEGER},
      </if>
      <if test="record.empName != null">
        emp_name = #{record.empName,jdbcType=VARCHAR},
      </if>
      <if test="record.gender != null">
        gender = #{record.gender,jdbcType=CHAR},
      </if>
      <if test="record.email != null">
        email = #{record.email,jdbcType=VARCHAR},
      </if>
      <if test="record.dId != null">
        d_id = #{record.dId,jdbcType=INTEGER},
      </if>
    </set>
    <if test="_parameter != null">
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByExample" parameterType="map">
    update tbl_emp
    set emp_id = #{record.empId,jdbcType=INTEGER},
      emp_name = #{record.empName,jdbcType=VARCHAR},
      gender = #{record.gender,jdbcType=CHAR},
      email = #{record.email,jdbcType=VARCHAR},
      d_id = #{record.dId,jdbcType=INTEGER}
    <if test="_parameter != null">
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByPrimaryKeySelective" parameterType="com.ssm.crud.bean.Employee">
    update tbl_emp
    <set>
      <if test="empName != null">
        emp_name = #{empName,jdbcType=VARCHAR},
      </if>
      <if test="gender != null">
        gender = #{gender,jdbcType=CHAR},
      </if>
      <if test="email != null">
        email = #{email,jdbcType=VARCHAR},
      </if>
      <if test="dId != null">
        d_id = #{dId,jdbcType=INTEGER},
      </if>
    </set>
    where emp_id = #{empId,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.ssm.crud.bean.Employee">
    update tbl_emp
    set emp_name = #{empName,jdbcType=VARCHAR},
      gender = #{gender,jdbcType=CHAR},
      email = #{email,jdbcType=VARCHAR},
      d_id = #{dId,jdbcType=INTEGER}
    where emp_id = #{empId,jdbcType=INTEGER}
  </update>
  
  
   <!--  ****** 自定义的 带部门信息 的两种查询  ******  -->
   <sql id="WithDept_Column_List">
  	e.emp_id, e.emp_name, e.gender, e.email, e.d_id,d.dept_id,d.dept_name
  </sql>
   <!--   List<Employee> selectByExampleWithDept(EmployeeExample example);
    Employee selectByPrimaryKeyWithDept(Integer empId); 
    -->
 <resultMap type="com.ssm.crud.bean.Employee" id="WithDeptResultMap">
  	<id column="emp_id" jdbcType="INTEGER" property="empId" />
    <result column="emp_name" jdbcType="VARCHAR" property="empName" />
    <result column="gender" jdbcType="CHAR" property="gender" />
    <result column="email" jdbcType="VARCHAR" property="email" />
    <result column="d_id" jdbcType="INTEGER" property="dId" />
    <!-- 指定联合查询出的部门字段的封装 -->
    <association property="department" javaType="com.ssm.crud.bean.Department">
    	<id column="dept_id" property="deptId"/>
    	<result column="dept_name" property="deptName"/>
    </association>
  </resultMap>
   <!-- 查询员工同时带部门信息 -->
  <select id="selectByExampleWithDept" resultMap="WithDeptResultMap">
	   select
	    <if test="distinct">
	      distinct
	    </if>
	    <include refid="WithDept_Column_List" />
		FROM tbl_emp e
		left join tbl_dept d on e.`d_id`=d.`dept_id`
	    <if test="_parameter != null">
	      <include refid="Example_Where_Clause" />
	    </if>
	    <if test="orderByClause != null">
	      order by ${orderByClause}
	    </if>
  </select>
  <select id="selectByPrimaryKeyWithDept" resultMap="WithDeptResultMap">
   	select 
    <include refid="WithDept_Column_List" />
    FROM tbl_emp e
	left join tbl_dept d on e.`d_id`=d.`dept_id`
    where emp_id = #{empId,jdbcType=INTEGER}
  </select>
  
  
</mapper>

八、Junit单元测试

需要在Maven中的pom.xml中，导入 junit.jar 包。

  <!--  一开始这里初始化 Junit 版本为3 ，
        当 eclipse 创建测试用例时，我选4版本的用例，发现又添加了Junit4 依赖包
        为了统一，我就在这里 改成 Juin4 依赖包，这样 eclipse创建 单元测试时就不会 重新添加依赖包了 -->
        <!-- https://mvnrepository.com/artifact/junit/junit -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>

方法一：代码加载spring容器

package com.ssm.crud.test;

import java.io.IOException;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.ssm.crud.mapper.DepartmentMapper;
import com.ssm.crud.mapper.EmployeeMapper;


public class CodeTest {
	
	DepartmentMapper departmentMapper;

	@Test
	public void testCRUD() throws IOException{

	    //1、创建SpringIOC容器  ，这个地方 却可以 正确加载 路径 xxx/target/classes/springIOC.xml
		
		//1、创建SpringIOC容器
		ApplicationContext ioc = new ClassPathXmlApplicationContext("springIOC.xml");
		//2、从容器中获取mapper
		EmployeeMapper bean = ioc.getBean(EmployeeMapper.class);
		
		System.out.println(bean.selectByPrimaryKey(1));
       		
	}

}

方法二：自动加载spring容器

需要在Maven的pom.xml中导入 spring-test.jar 包。

<!--Spring-test 单元测试 适配框架，用于在单元测试时，无需初始化就可以使用Spring 容器，及Spring注解 -->
<!-- https://mvnrepository.com/artifact/org.springframework/spring-test -->
<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-test</artifactId>
	<version>4.3.7.RELEASE</version>
</dependency>

package com.ssm.crud.test;

import java.io.IOException;

import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.ssm.crud.mapper.DepartmentMapper;
import com.ssm.crud.mapper.EmployeeMapper;


/**
 * 测试dao层的工作
 * @author lfy
 *推荐Spring的项目就可以使用Spring的单元测试，可以自动注入我们需要的组件
 *1、导入SpringTest模块
 *2、@ContextConfiguration指定Spring配置文件的位置
 *3、直接autowired要使用的组件即可
 */

//@RunWith这个是 junit-4.jar包 提供的注解, 而 SpringJUnit4ClassRunner.class 是spring-test 提供的类
@RunWith(SpringJUnit4ClassRunner.class)

//@ContextConfiguration 这个是 spring-test.jar包 提供的注解 , 用于启动 spring容器，方便直接获取spring容器中的bean
@ContextConfiguration(locations={"classpath:springIOC.xml"})
public class AnnotationTest {
	
	
	@Autowired
	DepartmentMapper departmentMapper;
	
	@Autowired
	EmployeeMapper employeeMapper;
	
	@Autowired
	SqlSession sqlSession;
	

	/**
	 * 测试DepartmentMapper
	 */

	@Test
	public void testCRUD() throws IOException{
	    

          System.out.println(employeeMapper.selectByPrimaryKey(1));
       
	 
		
		
		//1、插入几个部门
		departmentMapper.insertSelective(new Department(null, "开发部"));
		departmentMapper.insertSelective(new Department(null, "测试部"));
		
		//2、生成员工数据，测试员工插入
		employeeMapper.insertSelective(new Employee(null, "Jerry", "M", "[email protected]", 1));
		
		//3、批量插入多个员工；批量，使用可以执行批量操作的sqlSession。
		
//		for(){
//			employeeMapper.insertSelective(new Employee(null, , "M", "[email protected]", 1));
//		}
		EmployeeMapper mapper = sqlSession.getMapper(EmployeeMapper.class);
		for(int i = 0;i<1000;i++){
			String uid = UUID.randomUUID().toString().substring(0,5)+i;
			mapper.insertSelective(new Employee(null,uid, "M", uid+"@atguigu.com", 1));
		}
		System.out.println("批量完成");
		

		
	}

}

ps：关于加载log4j,也可以采用如下方法

public class JUnit4ClassRunner extends SpringJUnit4ClassRunner {
    static {
      try {
        // classpath 是 二进制 class文件 的执行根路径
        Log4jConfigurer.initLogging("classpath:log4j.xml");
      } catch (FileNotFoundException ex) {
        System.err.println("Cannot Initialize log4j");
      }
    }
    public JUnit4ClassRunner(Class<?> clazz) throws InitializationError {
      super(clazz);
    }
  }

@RunWith(JUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:springIOC.xml")

public class AnnotationTest {
    ...
}

Junit加载spring的runner（SpringJUnit4ClassRunner）要优先于spring加载log4j【log4j的自动默认加载功能】，因此采用普通方法，无法实现spring先加载log4j后被Junit加载。所以我们需要新建JUnit4ClassRunner类，修改SpringJUnit4ClassRunner加载log4j的策略。这样加载log4j就会优先于加载spring了。

数据库单元测试通过以后，就可以开始写web页面了。