自定义DTO、VO返回结果

xuejmnet大约 5 分钟

API

方法	支持后续链式	描述
`select(o->proxy)`	✅	用户可以自定义实现返回结果 (返回结果必须是 Proxy 类, 简单说就是 DTO 需要添加注解`@EntityProxy`)
`selectColumn(o->o.column())`	❌	用于用户返回单个字段, 当然也可以直接用`select(o->o.id())`需要`eq 2.0.0^`
`select(Class<TR>)`	❌	自动映射表和 DTO 对应关系, (对应关系是 DTO 映射的 columnName 和实体的 columnName 一致则映射), 比如两个属性都是`name`, 但是实体添加了`@Column(value="my_name")`那么 DTO 的`name`属性如果没有添加对应的注解, 将无法自动映射需要手动`as`来进行查询
`select(Class<TR>,expression)`	❌	用户可以对任意`DTO`对象的 class 进行自动或者手动映射比如 `select(DTO.class,o->Select.of(o.FETCHER.allFields(),o.name().as("myName")))`
`selectAutoInclude`	❌	支持用户返回任意列的数据库对象关系关联的数据, 比如嵌套结构: {name:.. , age:... ,list:[{...}, {...}]}
`selectAutoInclude expression`	❌	支持用户返回任意列的数据库对象关系关联的数据, 并且还可以`额外自定义join`返回其他数据, 比如嵌套结构: {name:.. , age:... ,address:...,list:[{...}, {...}]},其中 address 是用户地址的所属信息额外赋值

`select(o->proxy)`

该 api 返回自定义proxy对象比如我们创建了如下返回结果


@Data
@FieldNameConstants
@EntityProxy
@SuppressWarnings("EasyQueryFieldMissMatch")
public class BankCardVO {

    private String id;
    private String uid;
    /**
     * 银行卡号
     */
    private String code;
    /**
     * 银行卡类型借记卡 储蓄卡
     */
    private String type;

    private String userName;
    private String bankName;
}


@Data
@EntityProxy
@SuppressWarnings("EasyQueryFieldMissMatch")
@FieldNameConstants
public class DocUserVO {


    private String id;
    private String name;
    private String phone;
    private Integer age;
    private Long cardCount;

}

因为我们添加了@EntityProxy注解所以默认会生成BankCardVOProxy的 apt 类，其中我们的userName和bankName是非BankCard表内的数据,
所以需要我们额外赋值

部分列获取


List<DocBankCard> list = easyEntityQuery.queryable(DocBankCard.class)
        .where(bank_card -> bank_card.type().eq("储蓄卡"))
        .select(bank_card -> bank_card.FETCHER.id().code())
        .toList();

自定义VO查询




//手动join
List<BankCardVO> list = easyEntityQuery.queryable(DocBankCard.class)
        .leftJoin(DocUser.class, (bank_card, user) -> bank_card.uid().eq(user.id()))
        .leftJoin(DocBank.class, (bank_card, user, bank) -> bank_card.bankId().eq(bank.id()))
        .where((bank_card, user, bank) -> {
            user.name().like("小明");
            bank_card.type().eq("储蓄卡");
        })
        .select((bank_card, user, bank) -> {
            BankCardVOProxy r = new BankCardVOProxy();
            r.selectAll(bank_card);//相当于是查询所有的bankCard字段
            r.userName().set(user.name());
            r.bankName().set(bank.name());
            return r;
        }).toList();

==> Preparing: SELECT t.id,t.uid,t.code,t.type,t1.name AS user_name,t2.name AS bank_name FROM doc_bank_card t LEFT JOIN doc_user t1 ON t.uid = t1.id LEFT JOIN doc_bank t2 ON t.bank_id = t2.id WHERE t1.name LIKE ? AND t.type = ?
==> Parameters: %小明%(String),储蓄卡(String)

//上下两种结果一样
//隐式join
List<BankCardVO> list = easyEntityQuery.queryable(DocBankCard.class)
        .where(bank_card -> {
            bank_card.user().name().like("小明");
            bank_card.type().eq("储蓄卡");
        })
        .select(bank_card -> {
            BankCardVOProxy r = new BankCardVOProxy();
            r.selectAll(bank_card);//相当于是查询所有的bankCard字段
            r.userName().set(bank_card.user().name());
            r.bankName().set(bank_card.bank().name());
            return r;
        }).toList();
==> Preparing: SELECT t.id,t.uid,t.code,t.type,t1.name AS user_name,t2.name AS bank_name FROM doc_bank_card t LEFT JOIN doc_user t1 ON t1.id = t.uid LEFT JOIN doc_bank t2 ON t2.id = t.bank_id WHERE t1.name LIKE ? AND t.type = ?
==> Parameters: %小明%(String),储蓄卡(String)



//隐式select子查询
List<DocUserVO> list = easyEntityQuery.queryable(DocUser.class)
        .where(user -> {
            user.name().like("小明");
        })
        .select(user -> {
            DocUserVOProxy r = new DocUserVOProxy();
            r.selectAll(user);//相当于是查询所有的bankCard字段
            r.cardCount().set(user.bankCards().count());
            return r;
                }).toList();

==> Preparing: SELECT t.id,t.name,t.phone,t.age,(SELECT COUNT(*) FROM doc_bank_card t1 WHERE t1.uid = t.id) AS card_count FROM doc_user t WHERE t.name LIKE ?
==> Parameters: %小明%(String)

//手动select子查询
List<DocUserVO> list = easyEntityQuery.queryable(DocUser.class)
        .where(user -> {
            user.name().like("小明");
        })
        .select(user -> {
            DocUserVOProxy r = new DocUserVOProxy();
            r.selectAll(user);//相当于是查询所有的bankCard字段
            Query<Long> longQuery = easyEntityQuery.queryable(DocBankCard.class)
                    .where(bank_card -> {
                        bank_card.uid().eq(user.id());
                    }).selectCount();
            r.cardCount().setSubQuery(longQuery);
            return r;
        }).toList();

==> Preparing: SELECT t.id,t.name,t.phone,t.age,(SELECT COUNT(*) FROM doc_bank_card t1 WHERE t1.uid = t.id) AS card_count FROM doc_user t WHERE t.name LIKE ?
==> Parameters: %小明%(String)

//手动sql片段
List<DocUserVO> list = easyEntityQuery.queryable(DocUser.class)
        .where(user -> {
            user.name().like("小明");
        })
        .select(user -> {
            DocUserVOProxy r = new DocUserVOProxy();
            r.selectAll(user);//相当于是查询所有的bankCard字段
            r.cardCount().setSQL("IFNULL({0},1)",c -> c.expression(user.age()));
            return r;
        }).toList();

==> Preparing: SELECT t.id,t.name,t.phone,t.age,IFNULL(t.age,1) AS card_count FROM doc_user t WHERE t.name LIKE ?
==> Parameters: %小明%(String)

代理对象赋值

方法	描述
`set`	`r.set(value)`将常量或者数据库函数值赋值给`proxy`对象需要类型一致
`setNull`	赋值给列
`setSubQuery`	赋值一个子查询结果
`setSQL`	赋值自定义字符串 sql 片段
`setExpression`	同`set`无需类型一致(弱类型)
`selectAll`	同`t.*`将某张表的列自动映射匹配到结果对象中

`select(Class<TR>,expression)`

该 api 返回自定义结果对象比如我们创建了如下返回结果


@Data
@FieldNameConstants
@SuppressWarnings("EasyQueryFieldMissMatch")
public class BankCardVO {

    private String id;
    private String uid;
    /**
     * 银行卡号
     */
    private String code;
    /**
     * 银行卡类型借记卡 储蓄卡
     */
    private String type;

    private String userName;
    private String bankName;
}


@Data
@SuppressWarnings("EasyQueryFieldMissMatch")
@FieldNameConstants
public class DocUserVO {


    private String id;
    private String name;
    private String phone;
    private Integer age;
    private Long cardCount;

}

自定义VO查询

区别于select(o->proxy)我们使用class结果而不是代理对象来进行结果的接受


List<BankCardVO> list = easyEntityQuery.queryable(DocBankCard.class)
        .leftJoin(DocUser.class, (bank_card, user) -> bank_card.uid().eq(user.id()))
        .leftJoin(DocBank.class, (bank_card, user, bank) -> bank_card.bankId().eq(bank.id()))
        .where((bank_card, user, bank) -> {
            user.name().like("小明");
            bank_card.type().eq("储蓄卡");
        })
        .select(BankCardVO.class,(bank_card, user, bank) -> Select.of(
                //自动映射bank_card全属性等于select t.*但是以结果为主
                bank_card.FETCHER.allFields(),
                //添加FieldNameConstants,也可以使用方法引用BankCardVO::getUserName如果属性符合java的bean规范
                user.name().as(BankCardVO.Fields.userName),
                bank.name().as(BankCardVO.Fields.bankName)
        )).toList();




List<BankCardVO> list = easyEntityQuery.queryable(DocBankCard.class)
        .where(bank_card -> {
            bank_card.user().name().like("小明");
            bank_card.type().eq("储蓄卡");
        })
        .select(BankCardVO.class, bank_card -> Select.of(
                bank_card.FETCHER.allFields(),
                bank_card.user().name().as(BankCardVO.Fields.userName),
                bank_card.bank().name().as(BankCardVO.Fields.bankName)
        )).toList();




List<DocUserVO> list = easyEntityQuery.queryable(DocUser.class)
        .where(user -> {
            user.name().like("小明");
        })
        .select(DocUserVO.class,user -> Select.of(
                user.FETCHER.allFields(),
                user.bankCards().count().as(DocUserVO.Fields.cardCount)
        )).toList();



List<DocUserVO> list = easyEntityQuery.queryable(DocUser.class)
        .where(user -> {
            user.name().like("小明");
        })
        .select(DocUserVO.class,user -> Select.of(
                user.FETCHER.allFields(),
                user.expression().subQuery(()->{
                    return easyEntityQuery.queryable(DocBankCard.class)
                            .where(bank_card -> {
                                bank_card.uid().eq(user.id());
                            }).selectCount();
                }).as(DocUserVO.Fields.cardCount)
        )).toList();



List<DocUserVO> list = easyEntityQuery.queryable(DocUser.class)
        .where(user -> {
            user.name().like("小明");
        })
        .select(DocUserVO.class,user -> Select.of(
                user.FETCHER.allFields(),
                user.expression().sqlSegment("IFNULL({0},1)", c -> c.expression(user.age()),Integer.class).as(DocUserVO.Fields.cardCount)
        )).toList();

`selectAutoInclude(Class<TR>,expression)`

因为selectAutoInclude篇幅过多所以这边建议您重新跳转到链接结构化结果查询返回

自定义DTO、VO返回结果

# API

# select(o->proxy)

# 部分列获取

# 自定义VO查询

# 代理对象赋值

# select(Class<TR>,expression)

# 自定义VO查询

# selectAutoInclude(Class<TR>,expression)

API

`select(o->proxy)`

部分列获取

自定义VO查询

代理对象赋值

`select(Class<TR>,expression)`

自定义VO查询

`selectAutoInclude(Class<TR>,expression)`