为了减少spring中总是写错sql，特殊写了一个类尽可能地减少写mapper文件中sql的任务

为了防止sql注入我已经把所有生成sql的地方，加了’’，将他全部转成了文本，所以请勿担心sql注入的问题

java工具类

@Data
public class BaseCondition implements Cloneable {

    /**
     * where条件
     */
    @Getter
    private String criteria;

    /**
     * orderBy
     */
    private String orderByColumn;
    private String orderByType;

    /**
     * groupBy
     */
    private String groupBy;

    /**
     * 分页
     */
    private Integer start;
    private Integer length;


    public BaseCondition() {
        criteria = "";
    }

    /**
     * 手动添加条件语句
     *
     * @param condition
     * @return
     */
    public BaseCondition andCondition(String condition) {
        criteria += " and " + condition;
        return this;
    }

    /**
     * 字段排序
     *
     * @param column 哪一列
     * @param type   哪种形式
     * @return
     */
    public BaseCondition orderBy(String column, String type) {
        orderByColumn = column;
        orderByType = type;
        return this;
    }

    /**
     * 分页
     *
     * @param pageNum
     * @param length
     * @return
     */
    public BaseCondition limit(int pageNum, int length) {
        if(pageNum<1){
            pageNum = 1;
        }
        this.start = (pageNum - 1) * length;
        this.length = length;
        return this;
    }

    /**
     * isnull
     *
     * @param property 字段
     * @return
     */
    public BaseCondition andIsNull(String property) {
        criteria += " and " + property + " is null";
        return this;
    }

    /**
     * isNotNull
     *
     * @param property 字段
     * @return
     */
    public BaseCondition andIsNotNull(String property) {
        criteria += " and " + property + " is not null";
        return this;
    }

    /**
     * =
     *
     * @param property 字段
     * @param value    值
     * @return
     */
    public BaseCondition andEqualTo(String property, Object value) {
        criteria += " and " + property + " = '" + value + "'";
        return this;
    }

    /**
     * !=
     *
     * @param property 字段
     * @param value    值
     * @return
     */
    public BaseCondition andNotEqualTo(String property, Object value) {
        criteria += " and " + property + " != '" + value + "'";
        return this;
    }

    /**
     * >
     *
     * @param property 字段
     * @param value    值
     * @return
     */
    public BaseCondition andGreaterThan(String property, Object value) {
        if(value instanceof Date){
            value = DateUtils.format((Date)value);
        }
        criteria += " and " + property + " > '" + value + "'";
        return this;
    }

    /**
     * >=
     *
     * @param property 字段
     * @param value    值
     * @return
     */
    public BaseCondition andGreaterThanOrEqualTo(String property, Object value) {
        if(value instanceof Date){
            value = DateUtils.format((Date)value);
        }
        criteria += " and " + property + " >= '" + value + "'";
        return this;
    }

    /**
     * <
     *
     * @param property 字段
     * @param value    值
     * @return
     */
    public BaseCondition andLessThan(String property, Object value) {
        if(value instanceof Date){
            value = DateUtils.format((Date)value);
        }
        criteria += " and " + property + " < '" + value + "'";
        return this;
    }

    /**
     * <=
     *
     * @param property 字段
     * @param value    值
     * @return
     */
    public BaseCondition andLessThanOrEqualTo(String property, Object value) {
        if(value instanceof Date){
            value = DateUtils.format((Date)value);
        }
        criteria += " and " + property + " <= '" + value + "'";
        return this;
    }

    /**
     * in
     *
     * @param property 字段
     * @param values   值
     * @return
     */
    public BaseCondition andIn(String property, List values) {
        criteria += " and " + property + " in " + " (" + StringUtils.join(values.toArray(), ",") + ")";
        return this;
    }

    /**
     * not in
     *
     * @param property 字段
     * @param values   值
     * @return
     */
    public BaseCondition andNotIn(String property, List values) {
        criteria += " and " + property + " not in " + " (" + StringUtils.join(values.toArray(), ",") + ")";
        return this;
    }

    /**
     * between 范围选取 前包后不包
     *
     * @param property
     * @param value1
     * @param value2
     * @return
     */
    public BaseCondition andBetween(String property, Object value1, Object value2) {
        criteria += " and " + property + " between '" + value1 + "'" + " and '" + value2 + "'";
        return this;
    }

    /**
     * not between 范围选取 前包后不包
     *
     * @param property
     * @param value1
     * @param value2
     */
    public void andNotBetween(String property, Object value1, Object value2) {
        criteria += " and " + property + " not between '" + value1 + "'" + " and '" + value2 + "'";
    }

    /**
     * like
     *
     * @param property
     * @param value
     * @return
     */
    public BaseCondition andLike(String property, String value) {
        criteria += " and " + property + " like '" + value + "'";
        return this;
    }

    /**
     * not like
     *
     * @param property
     * @param value
     * @return
     */
    public BaseCondition andNotLike(String property, String value) {
        criteria += " and " + property + " not like '" + value + "'";
        return this;
    }

    /**
     * 去除条件语句最前面的and字符
     *
     * @return
     */
    public String getCriteria() {
        if (criteria != null && criteria.length() > 3) {
            return criteria.substring(4);
        }
        return null;
    }

    public String getOrderByColumn() {
        return "'" + orderByColumn + "'";
    }

    public String getGroupBy() {
        return "'" + groupBy + "'";
    }

    public int getStart() {
        if(start == null){
            return 0;
        }
        return start;
    }

    public int getLength() {
        if(length == null){
            return 0;
        }
        return length;
    }

    @Override
    public BaseCondition clone()
    {
        Object object = null;
        try {
            object = super.clone();
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        return (BaseCondition)object;
    }

使用方法

mapper sql 写法

注：orderBy 不可以拼接只能手写了（如果有好的解决办法欢迎联系我，分享给大家）

select
字段
from 表
left join 另一个表 on 关联条件


${criteria}


order by 字段

limit #{start},#{length}
\

java service写法

BaseCondition baseCondition = new BaseCondition();
baseCondition.andEqualTo(字段, 字段值);
 baseCondition.limit(pageNum,pageSize);