Java IPage paging operation Attach custom sql

   <dependency>
            <groupId></groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.1.2</version>
        </dependency>

@ApiModel(description = "User Entity")
public class User {

    /**
     * serialVersionUID
     */
    @ApiModelProperty(value = "Primary Key")
    private Integer id;

    @ApiModelProperty(value = "username")
    private String username;

    @ApiModelProperty(value = "Real Nickname")
    private String realname;

    @ApiModelProperty(value = "gender")
    private String sex;

    @ApiModelProperty(value = "Work number")
    private String jobNum;

    @ApiModelProperty(value = "Status 0 Enable 1 Disable")
    private Integer isDel;

    @ApiModelProperty(value = "department")
    private Integer departmentId;

    private String departmentName;

    @ApiModelProperty(value = "password")
    private String password;// User password
    @ApiModelProperty(value = "cell phone")
    private String mobile;// cell phone
    private Integer createUser;

    private Integer editUser;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private Date gmtCreate;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private Date gmtUpdate;
    }

   @PostMapping("/likeUser")
    @ApiOperation("Fuzzy Query-Pagination")
    public ApiResponse<User> getLikeUser(@RequestBody Map<String, Object> queryMap) {
        try {
            return ((queryMap));
        } catch (Exception e) {
            ("Fuzzy query - paging failed", e);
            return ("Fuzzy query - paging failed");
        }
    }

 IPage<User> getLikeUser(Map<String, Object> queryMap);

 @Override
    public IPage<User> getLikeUser(Map<String, Object> params) {
        long size = (((("limit")), "10"));
        long current = (((("page")), "1"));


        QueryWrapper<User> q = new QueryWrapper<>();

        Object username= ("username");

        Object realname= ("realname");

        Object sex= ("sex");

        Object jobNum= ("jobNum");

        Object mobile= ("mobile");
        // Sort        Object sort = ("sort");
        if (null != username && ().trim().length() > 0) {
            ().like(User::getUsername, username);
        }
        if (null != realname) {
            ().like(User::getRealname, realname);
        }
        if (null != jobNum) {
            ().eq(User::getJobNum, jobNum);
        }
        if (null != startTime && null != endTime) {
            // GE means GREATER THAN OR EQUAL is greater than or equal to            // LE is LESS THAN OR EQUAL is less than or equal to            ().ge(User::getCreateTime, startTime);
            ().le(User::getCreateTime, endTime);
        }
        if (("ASC")) {
            // Lift            ().orderByAsc(User::getCreateTime);
        } else if (("DESC")) {
            ().orderByDesc(User::getCreateTime);
        }
          IPage<USer> page = (
                new Page<>(current, size), q);
        return page;
    }

@Override
public IPage<TcmcAlarm> selectUSer(Map<String, Object> params) {
    long size = (((("limit")), "10"));
    long current = (((("page")), "1"));
    String id= ("devId").toString();
    String username= ("username").toString();
    // Use of pagination    Page<User> page = new Page<>(current, size);
    // Custom SQL    IPage<User> iPage = (page, username);
    return iPage;
}
// mapper
IPage<TcmcAlarm> selectUser(Page page, @Param("username") String username ;
// sql
<select  resultType="">
        select *
        from user
        where username LIKE CONCAT('%', #{username}, '%')
    </select>

// Complex splicing This is the simplest way to write it, directly splicing "," "#" ","_" "-" and so onString UNION = "UNION ALL "; // TB_SQL sql snippetString join = (UNION).join(TB_SQL);
Page<User> page = new Page<>(current, size);
        IPage<User> iPage = (page, join);
// mapper
IPage<User> selectUser(Page page, @Param("data") String data);
// xml
 <select  resultType="">
        ${data}
    </select>