Spring Data MongoDB--MongoTemplate查询数据--方法/实例

逃离我推掉我的手 2023-09-29 17:15 18阅读 0赞

原文网址：[Spring Data MongoDB--MongoTemplate查询数据--方法/实例\_IT利刃出鞘的博客-CSDN博客][Spring Data MongoDB--MongoTemplate_--_IT_-CSDN]

## 简介 ##

**说明**

本文用示例介绍Spring Data MongoDB（MongoTemplate）查询数据的方法。

**查询方法分类**

*  mongoTemplate.find //返回list
 *  mongoTemplate.findOne //返回1个（查询1个）
 *  mongoTemplate.findAll // 返回list（查询所有）

## 简单查询 ##

@Test
    public void testEqual2() {
        // 使用静态方法创建 Criteria
        Criteria criteria = Criteria.where("press").is("清华大学出版社");
    
        Query query = new Query(criteria);
        final List<Book> books = mongoTemplate.find(query, Book.class, "book");
        assert books.size() == 3;
    }

支持的查询有：

1.  等于：is
2.  大于：gt
3.  小于：lt
4.  大于等于：gte
5.  小于等于：lte
6.  不等于：ne
7.  模：mod

## 多条件查询 ##

@Test
    public void testAnd() {
        Criteria criteria = new Criteria();
        criteria.and("price")
            .gt(45)
            .and("press").is("清华大学出版社");
    
        Query query = new Query(criteria);
    
        List<Book> books = mongoTemplate.find(query, Book.class, BOOK_COLLECTION);
    }

## 排序与分页 ##

@Test
    public void testSortAndLimit() {
        Criteria criteria = Criteria.where("press").is("清华大学出版社");
        Query query = new Query(criteria);
    
        // with 方法设置排序
        query.with(Sort.by(Sort.Direction.ASC, "price"));
        // skip limit 方法设置分页
        query.skip(1).limit(10);
    
        final List<Book> books = mongoTemplate.find(query, Book.class, "book");
        assert  books.size() ==2;
    }

## 正则查询 ##

@Test
    public void testContain(){
        String name = "开发";
        Pattern pattern = Pattern.compile("^.*" + name + ".*$", Pattern.CASE_INSENSITIVE);
    
        Criteria criteria = Criteria.where("name").regex(pattern);
    
        Query query = new Query(criteria);
    
        final List<Book> books = mongoTemplate.find(query, Book.class, "book");
        assert books.size() == 1;
    }

## 数组查询 ##

### 匹配数组中单个值 ###

// 数组中包含查询单值
    @Test
    public void testArrayMatchSingle() {
        Criteria criteria = Criteria.where("tags").is("编程");
    
        Query query = new Query(criteria);
    
        List<Book> books = mongoTemplate.find(query, Book.class, "book");
    }

### 匹配数组中多个值 ###

// 数组中同时包含指定的多个值，不要求顺序
    @Test
    public void testArrayMatchAll() {
        Criteria criteria = Criteria.where("tags").all("编程", "程序设计");
    
        Query query = new Query(criteria);
    
        List<Book> books = mongoTemplate.find(query, Book.class, "book");
    }

### 匹配数组中元素个数 ###

@Test
    public void testArrayMatchSize() {
        Criteria criteria = Criteria.where("tags").size(4);
    
        Query query = new Query(criteria);
    
        List<Book> books = mongoTemplate.find(query, Book.class, "book");
    }

### 匹配指定位置元素 ###

// 满足特定索引下条件
    // 数组索引从 0 开始，匹配第二项就用 tags.1 作为键
    @Test
    public void testMatchIndex() {
        Criteria criteria = Criteria.where("tags.1").is("编程");
    
        Query query = new Query(criteria);
    
        List<Book> books = mongoTemplate.find(query, Book.class, "book");
    }

### 匹配整个数组 ###

// 元素个数和顺序都要匹配
    @Test
    public void testArrayMatch() {
        Criteria criteria = Criteria.where("tags").is(new String[]{"程序设计", "编程", "python"});
    
        Query query = new Query(criteria);
    
        List<Book> books = mongoTemplate.find(query, Book.class, "book");
    }

### 匹配子文档 ###

@Test
    public void testMatchSubDoc() {
        Criteria criteria = Criteria.where("authors.name").is("纪涵");
    
        Query query = new Query(criteria);
    
        List<Book> books = mongoTemplate.find(query, Book.class, "book");
    }

### elementMatch ###

@Test
    public void testElementMatch() {
        Criteria criteria = Criteria.where("authors").elemMatch(Criteria.where("name").is("谢希仁").and("sex").is("男"));
    
        Query query = new Query(criteria);
    
        List<Book> books = mongoTemplate.find(query, Book.class, "book");
    }

## 聚合查询 ##

### count ###

@Test
    public void testCount() {
        Query query = new Query();
        long ret = mongoTemplate.count(query, "book");
        System.out.println(ret);
    }

### distinct ###

@Test
    public void testDistinct(){
        List<String> distinctPress = mongoTemplate
            .findDistinct(new Query(), "press", "book", String.class);
        System.out.println(distinctPress);
    }

### sum、count、avg ###

@Test
    public void testSum() {
        Aggregation aggregation = Aggregation.newAggregation(
            Aggregation.project("_id", "press", "price"),
            Aggregation.group("press")
            .count().as("count")
            .sum("price").as("total")
            .avg("price").as("avg")
        );
    
        AggregationResults<Map> aggregationResults = mongoTemplate
            .aggregate(aggregation, "book", Map.class);
        List<Map> mappedResults = aggregationResults.getMappedResults();
        System.out.println(mappedResults);
    }

带有表达式的计算

@Test
    public void testSum2() {
        // 定义乘法表达式, 可以是两个字段相乘或者字段与数字相乘
        //同理，ArithmeticOperators 包含 加减乘除模等操作
    
        ArithmeticOperators.Multiply price = 
            ArithmeticOperators.valueOf("PRICE").multiplyBy(5);
       
        Aggregation aggregation = Aggregation.newAggregation(
            Aggregation.project("_id", "press", "PRICE"),
            Aggregation.group("press")
            .count().as("count")
            .sum(price).as("total")
            .avg(price).as("avg")
        );
    
        AggregationResults<Map> aggregationResults = mongoTemplate
            .aggregate(aggregation, "book", Map.class);
        List<Map> mappedResults = aggregationResults.getMappedResults();
        System.out.println(mappedResults);
    }

[Spring Data MongoDB--MongoTemplate_--_IT_-CSDN]: https://knife.blog.csdn.net/article/details/126874840