Mybatis批量更新数据库错误问题

import lombok.Data;

import javax.persistence.Table;
import java.io.Serializable;
import java.util.Date;

@Table(name = "tb_user")
@Data
public class User implements Serializable {

    private Integer id;

    private String username;

    private String password;

    private Date createTiem;

    private Date updateTime;
}

    <update id="updateBatch" parameterType="java.util.ArrayList">
        update tb_user
        set

        username = case
        <foreach collection="users" item="user">
            when id = #{user.id}
            <choose>
                <when test="user.username != null and user.username != ''">then #{user.username}</when>
                <otherwise>then username</otherwise>
            </choose>
        </foreach>
        end,

        password = case
        <foreach collection="users" item="user">
            when id = #{user.id}
            <choose>
                <when test="user.password != null and user.password != ''">then #{user.password}</when>
                <otherwise>then password</otherwise>
            </choose>
        </foreach>
        end,

        update_time = case
        <foreach collection="users" item="user">
            when id = #{user.id}
            <choose>
                <when test="user.updateTime != null">then #{user.updateTime}</when>
                <otherwise>then update_time</otherwise>
            </choose>
        </foreach>
        end

        where
        <foreach collection="users" item="user" separator="or">
            id = #{user.id}
        </foreach>
    </update>

        update_time = case
        <foreach collection="users" item="user">
            when id = #{user.id}
            <choose>
                <when test="true">then now()</when>
                <otherwise>then update_time</otherwise>
            </choose>
        </foreach>
        end