QueryDsl查询mongodb数据2

QueryDsl查询实例

上节已经生成了Query类，本文通过示例说明如何通过Query类实现灵活查询。

示例类及查询类

为了说明示例，这里定义简单的User类，以及依据User类生成的QUser类。

User类：

@Documentpublic class User {    @Id    private String id;    private String name;    private Integer age;    // standard getters and setters}

QUser类：

Query类是通过gradle插件自动生成的。

/** * QUser is a Querydsl query type for User */@Generated("com.mysema.query.codegen.EntitySerializer")public class QUser extends EntityPathBase<User> {    private static final long serialVersionUID = ...;    public static final QUser user = new QUser("user");    public final NumberPath<Integer> age = createNumber("age", Integer.class);    public final StringPath id = createString("id");    public final StringPath name = createString("name");    public QUser(String variable) {        super(User.class, forVariable(variable));    }    public QUser(Path<? extends User> path) {        super(path.getType(), path.getMetadata());    }    public QUser(PathMetadata<?> metadata) {        super(User.class, metadata);    }}

QueryDslPredicateExecutor接口

为了启用QueryDsl查询，需要简单继承QueryDslPredicateExecutor接口。

public interface UserRepository extends  MongoRepository<User, String>, QueryDslPredicateExecutor<User>

Eq

实现值相等查询。

QUser qUser = new QUser("user");Predicate predicate = qUser.name.eq("Eric");List<User> users = (List<User>) userRepository.findAll(predicate);

也可以指定多个条件

Predicate nameAndAgeAre = qUser.name.eq("Foo").and(qUser.age.eq(22));

StartingWith and EndingWith

实现字符串开头或结尾的模糊查询。

QUser qUser = new QUser("user");Predicate predicate = qUser.name.startsWith("A");List<User> users = (List<User>) userRepository.findAll(predicate);

字符串结尾查询：

QUser qUser = new QUser("user");Predicate predicate = qUser.name.endsWith("c");List<User> users = (List<User>) userRepository.findAll(predicate);

Between

实现范围查询

QUser qUser = new QUser("user");Predicate predicate = qUser.age.between(20, 50);List<User> users = (List<User>) userRepository.findAll(predicate);

组合查询

实现多个或组条件组合查询,摘录项目中的示例代码如下：

QUser qUser = new QUser("user");Predicate userCode = qUser.userCode.endsWith("4");Predicate userName = qUser.userName.endsWith("9").or(qUser.userName.endsWith("8"));BooleanBuilder example = new BooleanBuilder();example.and(userCode).or(userName);List<SysOrg> orgList = (List<SysOrg>)orgDao.findAll(example);assertThat(orgList,hasSize(3));

测试分页

QSysOrg qSysOrg;qSysOrg = new QSysOrg("sysOrg");Predicate predicate = qSysOrg.orgCode.startsWith("tx");Pageable pageable = PageRequest.of(0,5);Page<SysOrg> orgList = orgDao.findAll(predicate,pageable);assertThat(orgList.hasNext(),is(true));assertThat(orgList.getSize(),is(5));

测试排序

QSysOrg qSysOrg = QSysOrg.sysOrg;Predicate predicate = qSysOrg.orgCode.startsWith("tx");OrderSpecifier orderSpecifier = qSysOrg.orgCode.asc();List<SysOrg> orgList = (List<SysOrg>)orgDao.findAll(predicate,orderSpecifier);SysOrg org = (SysOrg) orgList.get(0);assertThat(org.getOrgCode(),is("tx001"));

总结

除了上述方法，还有很多功能强大的方法，如：like，contain等，留给善于探索的读者。