修改逻辑问题出来方案（在判断用户名相同的同时，在执行修改用户信息时如果用户名相同可以修改其它数据，但是用户名不作为修改）

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- mybatisPlus 核心库 -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.0.6</version>
        </dependency>

        <!-- thymeleaf模板引擎 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

        <!--redis-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>

        <!--    mysql驱动包    -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
            <version>5.1.41</version>
        </dependency>

        <!-- 引入阿里数据库连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.6</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <!--mybatis-plus 代码生成器依赖-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-generator</artifactId>
            <version>3.3.1.tmp</version>
        </dependency>

        <!--  swagger 依赖   -->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.9.2</version>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.9.2</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>RELEASE</version>
        </dependency>

        <!-- shiro -->
        <dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-spring</artifactId>
            <version>1.4.0</version>
        </dependency>
        <!-- thymeleaf模板引擎和shiro框架的整合 -->
        <dependency>
            <groupId>com.github.theborakompanioni</groupId>
            <artifactId>thymeleaf-extras-shiro</artifactId>
            <version>2.0.0</version>
        </dependency>

        <!--  热部署   -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>io.swagger</groupId>
            <artifactId>swagger-annotations</artifactId>
            <version>1.5.22</version>
        </dependency>
        <dependency>
            <groupId>io.swagger</groupId>
            <artifactId>swagger-models</artifactId>
            <version>1.5.22</version>
        </dependency>

        <!--json  jar相关jar包-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.9.0</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.7</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.7</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.23</version>
        </dependency>

        <dependency>
            <groupId>org.freemarker</groupId>
            <artifactId>freemarker</artifactId>
            <version>2.3.30</version>
        </dependency>


        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

package com.ckf.springboot_mysql_redis.service;

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.ckf.springboot_mysql_redis.entity.Users;
import com.baomidou.mybatisplus.extension.service.IService;
import com.ckf.springboot_mysql_redis.model.ResultFormat;
import io.swagger.models.auth.In;

/**
 * <p>
 * 服务类
 * </p>
 *
 * @author 安详的苦丁茶
 * @since 2020-05-02
 */
public interface UsersService extends IService<Users> {

    /**
     * 全查询用户信息
     *
     * @return
     */
    IPage<Users> selectUsersList(Page<Users> page);

    /**
     * 添加用户
     *
     * @param users
     * @return
     */
    ResultFormat saveUsers(Users users);

    /**
     * 修改用户
     *
     * @param users
     * @return
     */
    Integer updateUsers(Users users);

    /**
     * 删除用户
     *
     * @param userId
     * @return
     */
    Integer deleteUsersId(Integer userId);

}

 /**
     * 修改
     *
     * @param users
     * @return
     */
    @Override
    public Integer updateUsers(Users users) {
        logger.info("-----------------进入service实现层 修改用户信息-----------------");
        /**
         * 查询标签名称是否存在
         * 如果存在那就返回提示已经存在
         * 如果不存在那就修改
         */
        if (users != null) {
            if (users.getUserId() != null && !users.getUserName().isEmpty()) {
                Users pgLabelsByIdInfo = usersMapper.selectById(users.getUserId());
                AbstractWrapper wrapper = new QueryWrapper();
                wrapper.eq("user_name", users.getUserName());
                Users pgLabelsByNameInfo = usersMapper.selectOne(wrapper);

                /**
                 * 如果通过id查询的用户信息与前台传过来的名称一致
                 * 可修改其它数据
                 */
                if (pgLabelsByIdInfo != null) {
                    logger.info("pgLabelsByIdInfo={}", pgLabelsByIdInfo);
                    if (pgLabelsByIdInfo.getUserName().equals(users.getUserName())) {
                        Integer updateById = usersMapper.updateById(users);
                        if (updateById > 0) {
                            redisUtil.set("users:" + users.getUserId(), users);
                            return 200;
                        }
                    }
                }

                /**
                 * 从前台传过来的用户名称与id查询的名称不一致
                 * 再通过名称查询的数据为空就可以修改
                 */
                if (pgLabelsByNameInfo != null) {
                    logger.info("pgLabelsByNameInfo={}", pgLabelsByNameInfo);
                    if (!pgLabelsByNameInfo.getUserName().equals(pgLabelsByIdInfo.getUserName())) {
                        return 101;
                    }
                }

            }
        }

        /**
         * 如果用户名名称不一致就修改成 不存在的用户名称
         */
        Integer updateById = usersMapper.updateById(users);
        if (updateById > 0) {
            redisUtil.set("label:" + users.getUserName(), users);
            return 200;
        }

        return 100;
    }

    /**
     * 修改用户信息
     *
     * @param users
     * @return
     */
    @ApiOperation("修改用户信息接口")
    @PutMapping("/update")
    @ResponseBody
    public ResultFormat updatePgSorts(Users users) {

        users.getRegisterTime();
        users.setUpdateTime(TimeUtitl.dateTime());

        Integer insert = usersService.updateUsers(users);

        if (insert == 101) {
            logger.info("用户名已存在");
            return ResultUtil.error(101, "用户名已经存在");
        }
        if (insert == 200) {
            logger.info("修改成功");
            return ResultUtil.success();
        }

        return ResultUtil.error(100, "修改失败");

    }