Mastering EasyQuery: A Strongly Typed Java ORM with Real‑World Query Examples

Background

After several years of using Java and searching for a .NET‑style ORM that allows intuitive, strongly‑typed SQL generation, the author found existing solutions like MyBatis‑Plus insufficient for many scenarios, especially when dealing with soft deletes, joins, and complex expressions. Consequently, a new ORM named EasyQuery was developed, inspired by the completeness of .NET ORM ecosystems and designed to bring fluent, type‑safe query building to Java.

Basic Queries

Querying the first record:

Topic topic = easyQuery.queryable(Topic.class)
    .where(o -> o.eq(Topic::getId, "123"))
    .firstOrNull();

Querying a single record with an assertion:

Topic topic = easyQuery.queryable(Topic.class)
    .where(o -> o.eq(Topic::getId, "123"))
    .singleOrNull();

Querying multiple records:

List<Topic> topics = easyQuery.queryable(Topic.class)
    .where(o -> o.eq(Topic::getId, "123"))
    .toList();

Selecting specific columns:

Topic topic = easyQuery.queryable(Topic.class)
    .where(o -> o.eq(Topic::getId, "1"))
    .select(o -> o.column(Topic::getId).column(Topic::getTitle))
    .firstOrNull();

Paginated query:

EasyPageResult<Topic> page = easyQuery.queryable(Topic.class)
    .where(o -> o.isNotNull(Topic::getId))
    .toPageResult(1, 20);

Advanced Queries

Transforming an expression into a nested anonymous table:

Queryable<Topic> query = easyQuery.queryable(Topic.class)
    .where(o -> o.eq(Topic::getId, "1"))
    .select(Topic.class, o -> o.column(Topic::getId).column(Topic::getTitle));

List<Topic> list = query.leftJoin(Topic.class, (t, t1) -> t.eq(t1, Topic::getId, Topic::getId))
    .where((t, t1) -> {
        t1.eq(Topic::getId, "123");
        t.eq(Topic::getId, "456");
    })
    .toList();

Subquery example:

Queryable<BlogEntity> sub = easyQuery.queryable(BlogEntity.class)
    .where(o -> o.eq(BlogEntity::getId, "1"));

List<Topic> result = easyQuery.queryable(Topic.class)
    .where(o -> o.exists(sub.where(q -> q.eq(o, BlogEntity::getId, Topic::getId))))
    .toList();

Multi‑table left join:

Topic topic = easyQuery.queryable(Topic.class)
    .leftJoin(BlogEntity.class, (t, t1) -> t.eq(t1, Topic::getId, BlogEntity::getId))
    .where(o -> o.eq(Topic::getId, "3"))
    .firstOrNull();

Streaming Large Result Sets

try (JdbcStreamResult<BlogEntity> stream = easyQuery.queryable(BlogEntity.class)
        .where(o -> o.le(BlogEntity::getStar, 100))
        .orderByAsc(o -> o.column(BlogEntity::getCreateTime))
        .toStreamResult()) {
    int i = 0;
    for (BlogEntity blog : stream.getStreamIterable()) {
        // assertions verifying each field against expected values
        i++;
    }
} catch (SQLException e) {
    throw new RuntimeException(e);
}

Custom VO Mapping

List<QueryVO> list = easyQuery.queryable(Topic.class)
    .leftJoin(BlogEntity.class, (t, t1) -> t.eq(t1, Topic::getId, BlogEntity::getId))
    .leftJoin(SysUser.class, (t, t1, t2) -> t.eq(t2, Topic::getId, SysUser::getId))
    .where(o -> o.eq(Topic::getId, "123"))
    .where((t, t1, t2) -> t.eq(Topic::getId, "123").then(t1).like(BlogEntity::getTitle, "456").then(t2).eq(BaseEntity::getCreateTime, LocalDateTime.now()))
    .select(QueryVO.class, (t, t1, t2) ->
        t.column(Topic::getId)
         .then(t1).columnAs(BlogEntity::getTitle, QueryVO::getField1)
         .then(t2).columnAs(SysUser::getId, QueryVO::getField2)
    )
    .toList();

Dynamic Form‑Based Conditions

BlogQuery2Request req = new BlogQuery2Request();
req.setContent("标题");
req.setPublishTimeEnd(LocalDateTime.now());
req.setStatusList(Arrays.asList(1, 2));

List<BlogEntity> list = easyQuery.queryable(BlogEntity.class)
    .whereObject(req)
    .toList();

Basic Type Result

List<String> ids = easyQuery.queryable(Topic.class)
    .where(o -> o.eq(Topic::getId, "1"))
    .select(String.class, o -> o.column(Topic::getId))
    .toList();

Group By Queries

List<TopicGroupTestDTO> groups = easyQuery.queryable(Topic.class)
    .where(o -> o.eq(Topic::getId, "3"))
    .groupBy(o -> o.column(Topic::getId))
    .select(TopicGroupTestDTO.class, o -> o.columnAs(Topic::getId, TopicGroupTestDTO::getId)
        .columnCount(Topic::getId, TopicGroupTestDTO::getIdCount))
    .toList();

Native SQL Segment

String sql = easyQuery.queryable(H2BookTest.class)
    .where(o -> o.sqlNativeSegment("regexp_like({0},{1})", it -> it
        .expression(H2BookTest::getPrice)
        .value("^Ste(v|ph)en$")))
    .select(o -> o.columnAll())
    .toSQL();

Database Function Columns

EasyQuery can transparently handle columns that require database functions, such as Base64 decoding or PostgreSQL geographic types, without changing the Java model.

High‑Performance Encryption for LIKE

The library also provides encryption/decryption that works with the SQL LIKE operator, supporting both emoji and non‑emoji data.

Documentation: https://xuejm.gitee.io/easy-query-doc/guide/adv/column-sql-func-auto.html

Encryption guide: https://xuejm.gitee.io/easy-query-doc/guide/adv/column-encryption.html

Project Links

GitHub: https://github.com/xuejmnet/easy-query

Gitee: https://gitee.com/xuejm/easy-query

The article concludes with a brief thank‑you note and a source reference.