<?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.crj.mybatis.mapper.DynamicSQLMapper">
<!--    List<Emp> getEmpByCondition(Emp emp);-->
    <select id="getEmpByCondition" resultType="Emp">
        select * from t_emp where 1=1
        <if test="empName != null and empName != ''">
            and emp_name = #{empName}
        </if>
        <if test="age != null and age != ''">
            and age = #{age}
        </if>
        <if test="sex != null and sex != ''">
            and sex = #{sex}
        </if>
    </select>
</mapper>

<!--    List<Emp> getEmpByCondition(Emp emp);-->
    <select id="getEmpByCondition" resultType="Emp">
        select * from t_emp
        <where>
            <if test="empName != null and empName != ''">
                and emp_name = #{empName}
            </if>
            <if test="age != null and age != ''">
                and age = #{age}
            </if>
            <if test="sex != null and sex != ''">
                and sex = #{sex}
            </if>
        </where>
    </select>

<!--    List<Emp> getEmpByCondition(Emp emp);-->
    <select id="getEmpByCondition" resultType="Emp">
        select * from t_emp
        <trim prefix="where" suffixOverrides="and|or">
            <if test="empName != null and empName != ''">
                 emp_name = #{empName} and
            </if>
            <if test="age != null and age != ''">
                age = #{age} and
            </if>
            <if test="sex != null and sex != ''">
               sex = #{sex}
            </if>
        </trim>
    </select>

<!--    List<Emp> getEmpByChoose(Emp emp);-->
    <select id="getEmpByChoose" resultType="Emp">
        select * from t_emp
        <where>
            <choose>
                <when test="empName != null and empName != ''">
                    emp_name = #{empName}
                </when>
                <when test="age != null and age != ''">
                    age = #{age}
                </when>
                <when test="sex != null and sex != ''">
                    sex = #{sex}
                </when>
                <otherwise>
                    did = 1
                </otherwise>
            </choose>
        </where>
    </select>

<!--    int deleteMoreByArray(Integer[] eids);-->
    <delete id="deleteMoreByArray">
        delete * from t_emp where eid in
        <foreach collection="eids" item="eid" separator="," open="(" close=")">
            #{eid}
        </foreach>
    </delete>

    <sql id="emColumns">eid,emp_name,age,sex,email</sql>
    <select id="getEmpByChoose" resultType="Emp">
        select <include refid="emColumns"></include> from t_emp      
    </select>

sqlSession.clearCache();

public class Emp implements Serializable 

<?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.crj</groupId>
    <artifactId>MyBatis_MBG</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <!--依賴MyBatis核心包-->
    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.7</version>
        </dependency>
        <!--junit-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <!--mysql驅(qū)動(dòng)-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.3</version>
        </dependency>
        <!--log4j日志-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>
    <!--控制Maven在構(gòu)建過(guò)程中相關(guān)配置-->
    <build>
        <!--構(gòu)建過(guò)程用到的插件-->
        <plugins>
            <!--具體插件-->
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.0</version>
                <!--插件的依賴-->
                <dependencies>
                    <!--逆向工程的核心依賴-->
                    <dependency>
                        <groupId>org.mybatis.generator</groupId>
                        <artifactId>mybatis-generator-core</artifactId>
                        <version>1.3.2</version>
                    </dependency>
                    <!--數(shù)據(jù)庫(kù)連接池c3p0-->
                    <dependency>
                        <groupId>com.mchange</groupId>
                        <artifactId>c3p0</artifactId>
                        <version>0.9.2</version>
                    </dependency>
                    <!--mysql驅(qū)動(dòng)-->
                    <dependency>
                        <groupId>mysql</groupId>
                        <artifactId>mysql-connector-java</artifactId>
                        <version>5.1.8</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>
</project>

<?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>
    <!--
        targetRuntime：執(zhí)行生成的逆向工程的版本
            MyBatis3Simple：生成基本的CRUD
            MyBatis：生成帶條件的CRUD
    -->
    <!-- 是否去除自動(dòng)生成的注釋 true：是 ： false:否 -->
    <context id="DB2Tables" targetRuntime="MyBatis3Simple">
        <!-- 數(shù)據(jù)庫(kù)連接 -->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/mybatis"
                        userId="root"
                        password="123456">
        </jdbcConnection>
        <!--
            javaBean的生成策略
            生成model模型，對(duì)應(yīng)的包路徑，以及文件存放路徑(targetProject)，targetProject可以指定具體的路徑
            也可以使用“MAVEN”來(lái)自動(dòng)生成，這樣生成的代碼會(huì)在target/generatord-source目錄下
        -->
        <javaModelGenerator targetPackage="com.crj.mybatis.pojo" targetProject=".\src\main\java">
            <!--是否能夠使用子包-->
            <property name="enableSubPackages" value="true" />
            <!-- 從數(shù)據(jù)庫(kù)返回的值被清理前后的空格  -->
            <property name="trimStrings" value="true" />
        </javaModelGenerator>
        <!--
            SQL映射文件的生成策略
            對(duì)應(yīng)的mapper.xml文件
        -->
        <sqlMapGenerator targetPackage="com.crj.mybatis.mapper" targetProject=".\src\main\resources">
            <property name="enableSubPackages" value="true" />
        </sqlMapGenerator>
        <!-- 對(duì)應(yīng)的Mapper接口類文件的生成策略 -->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.crj.mybatis.mapper" targetProject=".\src\main\java">
            <property name="enableSubPackages" value="true" />
        </javaClientGenerator>
        <!-- 逆向分析的表 -->
        <table tableName="t_emp" domainObjectName="Emp"/>
        <table tableName="t_dept" domainObjectName="Dept"/>
    </context>
</generatorConfiguration>

EmpExample example = new EmpExample();
//這里可以借助example.createCriteria().and開(kāi)頭的方法來(lái)設(shè)置查詢條件
example.createCriteria().andEmpNameEqualTo("荔枝");
mapper.selectByExample(example);