案例27-单表从9个更新语句调整为2个

<dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <!--junit-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

driver=com.mysql.jdbc.Driver
url=jdbc:mysql:服务器IP:3306/wzill?useSSL=false&;useUnicode=true;CharacterEncoding=UTF-8
username=数据库账号
password=数据库密码

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-config.dtd">
<!--configuration mybatis的核心配置文件-->
<configuration>
<!--引入外部配置文件-->
    <properties resource="db.properties"/>
    <!--配置-->
    <settings>
        <!--标准日志工厂设置-->
        <setting name="logImpl" value="STDOUT_LOGGING"/>
<!--显示的开启全局缓存-->
        <setting name="cacheEnabled" value="true"/>
    </settings>
<!--可以给实体类取别名-->
    <typeAliases>
      <!--<typeAlias type="com.kuang.pojo.User" alias="User"/>-->
        <!--可以指定一个包名，MyBatis会在包名下面搜索需要的Java Bean-->
        <package name="com.wzl.CommonUse.pojo"/>
    </typeAliases>
    <!--environments 后面的s表示这是一个复数，可以编写多套环境  default表示默认的环境为development-->
    <environments default="development">
        <!--编写一套环境 名称为configuration-->
        <environment id="development">
            <!--jdbc的事务管理-->
            <transactionManager type="JDBC"/>
            <!--配置数据库相关数据-->
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <!--userSSL是一个按权连接 &amp是一个转移符 等同于and  CharacterEncoding=utf-8可以保证输入数据库的数据不乱码-->
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
<!--绑定接口-->
    <mappers>
        <mapper class="com.wzl.CommonUse.dao.UserMapper"/>
    </mappers>
</configuration>

public class MybatisUtils {
    private  static SqlSessionFactory sqlSessionFactory;
    //静态代码块：一旦初始化就加载
    static{
        try {
            //使用Mybatis第一步：获取sqlSessionFactory对象
            //获取资源，直接读到mybatis-config.xml
            String resource = "mybatis-config.xml";
            //需要用到输入流（InputStream） 把resource类加载进来
            InputStream inputStream = Resources.getResourceAsStream(resource);
            //通过build把输入流加载进来
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static SqlSession getSqlSession() {
        //openSession中有自动commit（提交）事务的方法，加上true就能实现
        return sqlSessionFactory.openSession(true);
    }
}

<update id="updateUser">
        update user
        <trim prefix="SET" suffixOverrides=",">
            <if test="userPojo.uid != null">uid = #{userPojo.uid}</if>
            <if test="userPojo.id != null">id = #{userPojo.id}</if>
            <if test="userPojo.name != null">name = #{userPojo.name}</if>
            <if test="userPojo.age != null">age = #{userPojo.age}</if>
            <if test="userPojo.username != null">username = #{userPojo.username}</if>
            <if test="userPojo.password != null">password = #{userPojo.password}</if>
            <if test="userPojo.email != null">email = #{userPojo.email}</if>
            <if test="userPojo.phone != null">phone = #{userPojo.phone}</if>
            <if test="userPojo.addr != null">addr = #{userPojo.addr}</if>
            <if test="userPojo.state != null">state = #{userPojo.state}</if>
        </trim>
        where state = 2
        <if test="conditionParam.addr != null"> and addr = #{conditionParam.addr}</if>
        <if test="conditionParam.phone != null">and phone = #{conditionParam.phone}</if>
        <if test="conditionParam.name != null">and name = #{conditionParam.name}</if>
        <if test="conditionParam.age != null">and age = #{conditionParam.age}</if>
        <if test="conditionParam.username != null">and username = #{conditionParam.username}</if>
        <if test="conditionParam.password != null">and password = #{conditionParam.password}</if>
    </update>

public class Client{
    @Test
    public void test(){
        //获取数据库连接
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        //进行更新操作
        UserPojo UserPojo1 = new UserPojo();
        UserPojo UserPojo2 = new UserPojo();
        //假删除某个课的某个班的所有信息
        UserPojo1.setUsername("223667994");
        UserPojo2.setUsername("bbb");
        //进行调用
        userMapper.updateUser(UserPojo1,UserPojo2);
    }
}