summary -- hibernate -- select

查询1：sqlQuery返回 Map

Session session = hibernateTemplate.getSessionFactory().openSession();
List<Map<String, Object>> list = null;
try {
    StringBuilder sb = new StringBuilder();
    sb.append("select s.*, c.name as className from Course c");
    sb.append(" left join Student s on s.classId=c.id");

    SQLQuery sqlQuery = session.createSQLQuery(sb.toString());
    sqlQuery.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);
    list = sqlQuery.list();
} catch (Exception e) {
    e.printStackTrace();
} finally {
    session.close();
}
return list;

查询2：返回的是实体类

Session session = hibernateTemplate.getSessionFactory().openSession();
List<Map<String, Object>> list = null;
try {
    StringBuilder sb = new StringBuilder();
    sb.append("from Student");
    sb.append(" where id='12345'");

    Query query = session.createQuery(sb.toString());
　  // session.createSQLQuery(sql).addEntity(Studnet.class);
    list = query.list();
} catch (Exception e) {
    e.printStackTrace();
} finally {
    session.close();
}
return list;

查询3： 需创建vo类

Session session = hibernateTemplate.getSessionFactory().openSession();
List<Map<String, Object>> list = null;
try {
    StringBuilder sb = new StringBuilder();
    sb.append("select s.*, c.name as className from Course c");
    sb.append(" left join Student s on s.classId=c.id");

    SQLQuery sqlQuery = session.createSQLQuery(sb.toString());
    sqlQuery.addScalar("id", Hibernate.INTEGER);
    sqlQuery.addScalar("name", Hibernate.STRING);
    sqlQuery.addScalar("age", Hibernate.INTEGER);
    sqlQuery.addScalar("className", Hibernate.STRING);
    
    sqlQuery.setResultTransformer(Transformers.aliasToBean(StudentVo.class));
    list = sqlQuery.list();
} catch (Exception e) {
    e.printStackTrace();
} finally {
    session.close();
}
return list;

@Data
public class StudentVo {
    private int id;
    private String name;
    private int age;
    private Course course;
}