mybatis 嵌套List

Java个体户2025-04-15 18:20

主查询

xml 复制代码

<!-- 查询车型列表（基于 pdtAliasId 查询） -->
<select id="selectNestedList" resultMap="NestedResultMap">
    SELECT
    t.MAKE,
    t.MODEL,
    t.YEAR

    FROM L_CAR_MODEL_YEAR_${lan} t

第一层嵌套

xml 复制代码

<resultMap id="NestedResultMap" type="com.launch.lcar.model.NestedCarModelResult">
    <result property="make" column="MAKE"/>
    <collection property="models" ofType="com.launch.lcar.model.NestedCarModelResult$ModelDetail"
                resultMap="ModelDetailResultMap"/>
</resultMap>

第二层嵌套

xml 复制代码

<resultMap id="ModelDetailResultMap" type="com.launch.lcar.model.NestedCarModelResult$ModelDetail">
    <result property="model" column="MODEL"/>
    <collection property="years" ofType="java.lang.String" resultMap="YearResultMap"/>
</resultMap>

第三层嵌套

xml 复制代码

<resultMap id="YearResultMap" type="java.lang.String">
    <result column="YEAR"/>
</resultMap>

嵌套实体类

java 复制代码

public class NestedCarModelResult implements Serializable {
    private String make;
    private List<ModelDetail> models;

    public static class ModelDetail implements Serializable {
        private String model;
        private List<String> years;

返回结果

json 复制代码

{
    "code": 0,
    "flag": 0,
    "msg": "success",
    "data": [
        {
            "make": "别克（中国）",
            "models": [
                {
                    "model": "君威",
                    "years": [
                        "2009",
                        "2010",
                        "2011",
                        "2012",
                        "2013",
                        "2014",
                        "2015",
                        "2016",
                        "2017",
                        "2018",
                        "2019",
                        "2020",
                        "2021",
                        "2022",
                        "2023",
                        "2024"
                    ]
                }
            ]
        }
    ]
}

总结

单层嵌套和多层嵌套，都可以

单层嵌套，就写一层

多层嵌套，就写多层