【MongoDB】SpringBoot - 分页与去重查询

伪代码
db.集合.distinct("字段名")
示例代码
//去重（查询性别种类）
db.hero.distinct('gender')
// 测试 结果
[
    "女",
    "男"
]
//根据条件去重(查询年龄在12至19岁之间的年龄列表)
db.hero.distinct('age',{'age':{$gt:12,$lt:19}})
// 测试 结果
[
    13,
    14,
    15,
    16,
    17,
    18
]

//去重（查询性别种类）
     @Test
    void findDistinctTest(){
        Query query =new Query();
        List<String> genders =  mongoTemplate.findDistinct(query,"gender","hero",String.class);
        genders.stream().forEach(System.out::println);
}

//根据条件去重(查询年龄在12至19岁之间的年龄列表)
@Test
void findDistinctByAgeTest(){
    Query query =new Query();
    query.addCriteria(new Criteria("age").gt(12).lt(19));
    List<Integer> genders =  mongoTemplate.findDistinct(query,"age","hero",Integer.class);
    genders.stream().forEach(System.out::println);
}

伪代码
db.集合.find().limit(行数)
示例代码
// 分页
db.hero.find().limit(2)
// 测试结果
// 1
{
    "_id": ObjectId("6292e32a63fd032330a30ba4"),
    "name": "陈",
    "gender": "男",
    "age": NumberInt("55"),
    "dt": NumberLong("1653793578431116400")
}


// 2
{
    "_id": ObjectId("6292e8c0fa63510b5822a5f4"),
    "name": "席盆哲",
    "gender": "男",
    "age": NumberInt("54"),
    "dt": NumberLong("1653795008039"),
    "_class": "com.zuoyang.springbootmongo.domain.Hero"
}
// 根据条件分页(查询年龄在12至19岁之间，性别为男的两条数据)
db.hero.find({'age':{$gt:12,$lt:19},'gender':'男'}).limit(2)
// 测试结果
// 1
{
    "_id": ObjectId("6292e8c1fa63510b5822a654"),
    "name": "但装赣",
    "gender": "男",
    "age": NumberInt("13"),
    "dt": NumberLong("1653795009258"),
    "_class": "com.zuoyang.springbootmongo.domain.Hero"
}


// 2
{
    "_id": ObjectId("6292e8c1fa63510b5822a7da"),
    "name": "富入",
    "gender": "男",
    "age": NumberInt("13"),
    "dt": NumberLong("1653795009741"),
    "_class": "com.zuoyang.springbootmongo.domain.Hero"
}

伪代码
db.集合.find().count()
示例代码
// 统计
db.hero.find().count()
// 测试结果
// 1
1001001
// 根据条件统计（统计年龄在12至19岁之间，性别为男的数量）
db.hero.find({'age':{$gt:12,$lt:19},'gender':'男'}).count()
// 测试结果
// 1
35404

 @Test
    void findTest(){
        Query query =new Query();
//        Criteria criteria = new Criteria("age").is(15);
//        query.addCriteria(criteria);
        int pageSize = 2; //行数
        int pageConut = 1; //页数
        // 统计总行数
        long count = mongoTemplate.count(query,Hero.class);
        System.out.println("总行数： "+count);
        Pageable pageable = PageRequest.of(pageConut,pageSize);
        query.with(pageable);


        List<Hero> heroes = mongoTemplate.find(query,Hero.class);
        for (Hero hero : heroes) {
            System.out.println(hero.getName());
        }
    }

@Test
void findByAgeTest(){
    Query query =new Query();
    Criteria criteria = new Criteria("age").is(15);
    query.addCriteria(criteria);
    int pageSize = 2; //行数
    int pageConut = 1; //页数
    // 统计总行数
    long count = mongoTemplate.count(query,Hero.class);
    System.out.println("总行数： "+count);
    Pageable pageable = PageRequest.of(pageConut,pageSize);
    query.with(pageable);


    List<Hero> heroes = mongoTemplate.find(query,Hero.class);
    for (Hero hero : heroes) {
        System.out.println("姓名: "+hero.getName()+" 年龄： "+hero.getAge());
    }
}

/**
 * 获取性别列表（前端下拉列表数据类型）
 * @return
 */
@Override
public List<Map> findGenderList(){
    List<Map> datas = new ArrayList();
    Query query =new Query();
    for (String s : mongoTemplate.findDistinct(query, "gender", "hero", String.class)) {
        Map map = new HashMap();
        map.put("lable",s);
        map.put("value",s);
        datas.add(map);
    }
    return datas;
}

/**
 * 获取性别列表（前端下拉列表数据类型）测试用例
 */
@Test
void findGenderList(){
    System.out.println(heroService.findGenderList());
}

/**
 * 分页查询
 * @param pageConut 页数
 * @param pageSize 行数
 * @return
 */
@Override
public Map pageHeros(int pageConut,int pageSize){
    Map data = new HashMap();
    Query query =new Query();
    // 统计总行数
    long count = mongoTemplate.count(query, Hero.class);
    Pageable pageable = PageRequest.of(pageConut,pageSize);
    query.with(pageable);
    List<Hero> heroes = mongoTemplate.find(query,Hero.class);
    data.put("pageConut",pageConut);
    data.put("pageSize",pageSize);
    data.put("count",count);
    data.put("data",heroes);
    return data;
}

/**
 * 分页查询 测试用例
 * @return
 */
@Test
void pageHerosTest(){
   Map map= heroService.pageHeros(1,3);
    System.out.println("pageConut: " + map.get("pageConut"));
    System.out.println("data: " + map.get("data"));
    System.out.println("count: " + map.get("count"));
    System.out.println("pageSize: " + map.get("pageSize"));
}

/**
 * 分页条件查询
 * @param pageConut 页数
 * @param pageSize 行数
 * @param gender 性别
 * @return
 */
@Override
public Map pageHerosByGender(int pageConut, int pageSize, String gender){
    Map data = new HashMap();
    Query query =new Query();
    query.addCriteria(new Criteria("gender").is(gender));
    // 统计总行数
    long count = mongoTemplate.count(query, Hero.class);
    Pageable pageable = PageRequest.of(pageConut,pageSize);
    query.with(pageable);
    List<Hero> heroes = mongoTemplate.find(query,Hero.class);
    data.put("pageConut",pageConut);
    data.put("pageSize",pageSize);
    data.put("count",count);
    data.put("data",heroes);
    return data;
}

/**
 * 分页条件查询 测试用例
 * @return
 */
@Test
void pageHerosByGender(){
    Map map= heroService.pageHerosByGender(1,3,"男");
    System.out.println("pageConut: " + map.get("pageConut"));
    System.out.println("data: " + map.get("data"));
    System.out.println("count: " + map.get("count"));
    System.out.println("pageSize: " + map.get("pageSize"));
}