search
HomeJavajavaTutorialJava implements mongodb, generic encapsulation, addition, deletion, query, modification, conditional query and other operations

This article implements a general generic encapsulation implementation class, which requires a given collection object, similar to the table corresponding to java in mysql; the idea is to parse out all non-null fields of the given object and save them into a BasicDBObject, here Be sure to ensure that the java object has the same name as the document field in mongodb, because in order to achieve universality, the code defaults to the query field of the java object as the BasicDBObject.

Core code 1: This is to convert java objects into query conditions.

/**
     * 通过反射获取非空字段信息
     * @param record
     * @param <Q>
     * @return
     */
    private <Q> BasicDBObject getCondition(Q record) {
        BasicDBObject cond = new BasicDBObject();
        Class clazz = record.getClass();
        Field[] fields = clazz.getDeclaredFields();
        for (Field field : fields) {
            try {
                field.setAccessible(true);
                Object value = field.get(record);
                if (value != null)
                    cond.put(field.getName(), value);
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        }
        return cond;
    }

Core code 2: This is to convert the queried document into a java object. Here, the fields of the default java object are the same as the fields of the database document. All fields of the user-defined object are dynamically obtained using java reflection. , and then perform the assignment. I judged the int and long types separately during the assignment process, because when inserting into mongodb, it is usually stored as double, which will cause a transformation error.

/**
     * 将结果转化为自定义对象
     * @param document
     * @param target
     * @param <Q>
     * @return
     */
    private <Q> Q parseToObject(Document document, Class<Q> target) {
        try {
            Q result = target.newInstance();
            Field[] fields = target.getDeclaredFields();
            for (Field f : fields) {
                f.setAccessible(true);
                Object value = document.get(f.getName());
                if (value == null)
                    continue;
                else if (f.getType() == Integer.class)
                    f.set(result, ((Number) value).intValue());
                else if (f.getType() == Long.class)
                    f.set(result, ((Number) value).longValue());
                else
                    f.set(result, document.get(f.getName(), f.getType()));
            }
            return result;
        } catch (IllegalAccessException e) {
            e.printStackTrace();
            return null;
        } catch (InstantiationException e) {
            e.printStackTrace();
            return null;
        }
    }

Calling method: First convert the query parameters. When querying, id is used to determine the positive and negative order, so there must be an id identification field in the default database.

public <Q> List<Q> queryByCondition(BaseQuery<Q> query,boolean up) {
        Q record = query.getQuery();
        BasicDBObject cond = getCondition(record);
        FindIterable<Document> findIterable;
        if (query.getStart() != null && query.getRows() != null)
            findIterable = thisCollection().find(cond)
                    .sort(new BasicDBObject("id", up ? 1 : -1))
                    .skip((query.getStart() - 1) * query.getRows())
                    .limit(query.getRows());
        else
            findIterable = thisCollection().find(cond)
                    .sort(new BasicDBObject("id", up ? 1 : -1));
        MongoCursor<Document> iterator = findIterable.iterator();
        List<Q> result = new ArrayList<>();
        while (iterator.hasNext()) {
            Document document = iterator.next();
            result.add((Q) parseToObject(document, record.getClass()));
        }
        iterator.close();
        return result;
    }

The BaseQuery passed in here is as follows: the query inside is a java object that needs to be queried, and start&rows is used for paging. The lombok plug-in is used here, which simplifies a lot of gettter&setter and other codes.

@Setter
@Getter
@NoArgsConstructor
@AllArgsConstructor
@Data
@Accessors(chain = true)
public class BaseQuery<Q> {
    private Integer start;
    private Integer rows;
    private Q query;

    public BaseQuery(Class clazz) {
        try {
            this.query = (Q) clazz.newInstance();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
    }
}

Test condition query method: The entities used here are as follows:

@Data
@AllArgsConstructor
@NoArgsConstructor
@Accessors(chain = true)
public class User_info {
    private Integer id;

    private String name;

    private Integer age;

    private Integer role;
}
public static void main(String[] args) {
        User_info record = new User_info();
        BaseQuery<User_info> query = new BaseQuery<>();
        query.setQuery(record);

        BaseMongoDao dao = new BaseMongoDao("test");
        List<User_info> result = dao.queryByCondition(query, true);
        for (User_info user : result) {
            System.out.println(user);
        }
    }

Because the query conditions used here are empty, all items in the database will be matched:

Java implements mongodb, generic encapsulation, addition, deletion, query, modification, conditional query and other operations

Now test the data with permission set to 1:

public static void main(String[] args) {
        User_info record = new User_info();
        record.setRole(1);
        BaseQuery<User_info> query = new BaseQuery<>();
        query.setQuery(record);

        BaseMongoDao dao = new BaseMongoDao("test");
        List<User_info> result = dao.queryByCondition(query, true);
        for (User_info user : result) {
            System.out.println(user);
        }
    }

Output:

Java implements mongodb, generic encapsulation, addition, deletion, query, modification, conditional query and other operations

This conditional query method is an example , other deletions, additions, and modifications are all based on this principle, as follows:

1.public List queryByCondition(BaseQuery query,boolean up)

2.public Integer queryCoditionCount(BaseQuery query)

3.public boolean insertOne(Q record)

4.public boolean insertList(List records)

5.public boolean deleteById(Integer id)

6.public boolean deleteByIds(List ids)

7.public void updateById(Q record)

Put all the code:

package cn.wzy.dao;

import com.mongodb.*;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;
import org.bson.Document;
import org.cn.wzy.query.BaseQuery;
import org.cn.wzy.util.PropertiesUtil;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;

/**
 * Create by Wzy
 * on 2018/7/28 18:15
 * 不短不长八字刚好
 */
public class BaseMongoDao {

    private static final MongoClient mongoClient;

    private static final MongoDatabase mongo;

    static {
        MongoClientOptions options = MongoClientOptions.builder()
                .connectionsPerHost(150)
                .maxWaitTime(2000)
                .socketTimeout(2000)
                .maxConnectionLifeTime(5000)
                .connectTimeout(5000).build();
        ServerAddress serverAddress = new ServerAddress(PropertiesUtil.StringValue("mongo.host"),
                PropertiesUtil.IntegerValue("mongo.port"));
        List addrs = new ArrayList<>();
        addrs.add(serverAddress);
        MongoCredential credential = MongoCredential.createScramSha1Credential(
                PropertiesUtil.StringValue("mongo.user")
                , PropertiesUtil.StringValue("mongo.db")
                , PropertiesUtil.StringValue("mongo.pwd").toCharArray());
        mongoClient = new MongoClient(addrs, credential, options);
        mongo = mongoClient.getDatabase(PropertiesUtil.StringValue("mongo.db"));
    }

    public BaseMongoDao(String colName) {
        this.colName = colName;
    }

    private String colName;

    private MongoCollection thisCollection() {
        return mongo.getCollection(colName);
    }


    public <Q> List<Q> queryByCondition(BaseQuery<Q> query,boolean up) {
        Q record = query.getQuery();
        BasicDBObject cond = getCondition(record);
        FindIterable<Document> findIterable;
        if (query.getStart() != null && query.getRows() != null)
            findIterable = thisCollection().find(cond)
                    .sort(new BasicDBObject("id", up ? 1 : -1))
                    .skip((query.getStart() - 1) * query.getRows())
                    .limit(query.getRows());
        else
            findIterable = thisCollection().find(cond)
                    .sort(new BasicDBObject("id", up ? 1 : -1));
        MongoCursor<Document> iterator = findIterable.iterator();
        List<Q> result = new ArrayList<>();
        while (iterator.hasNext()) {
            Document document = iterator.next();
            result.add((Q) parseToObject(document, record.getClass()));
        }
        iterator.close();
        return result;
    }

    public  Integer queryCoditionCount(BaseQuery query) {
        Q record = query.getQuery();
        BasicDBObject cond = getCondition(record);
        return (int) thisCollection().countDocuments(cond);
    }

    public  boolean insertOne(Q record) {
        BasicDBObject cond = getCondition(record);
        try {
            int top = getTop();
            cond.put("id",++top);
            thisCollection().insertOne(new Document(cond));
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

    public  boolean insertList(List records) {
        try {
            List list = new ArrayList<>(records.size());
            if (!changeIds(records))
                return false;
            for (Q record : records) {
                list.add(new Document(getCondition(record)));
            }
            thisCollection().insertMany(list);
            return true;
        }catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

    public boolean deleteById(Integer id) {
        try {
            if (id == null)
                return false;
            thisCollection().deleteOne(new BasicDBObject("id",id));
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

    public  boolean deleteByIds(List ids) {
        BasicDBObject cond = new BasicDBObject("id",new BasicDBObject("$in",ids.toArray()));
        try {
            thisCollection().deleteMany(cond);
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

    /**
     * 只通过id更改,查询就只是搜索id
     * @param record
     * @param 
     */
    public  void updateById(Q record) {
        BasicDBObject cond = getCondition(record);
        BasicDBObject update = new BasicDBObject("$set",cond);
        BasicDBObject query = new BasicDBObject("id",cond.get("id"));
        thisCollection().updateOne(query,update);
    }

    /**
     * 通过反射获取非空字段信息
     * @param record
     * @param <Q>
     * @return
     */
    private <Q> BasicDBObject getCondition(Q record) {
        BasicDBObject cond = new BasicDBObject();
        Class clazz = record.getClass();
        Field[] fields = clazz.getDeclaredFields();
        for (Field field : fields) {
            try {
                field.setAccessible(true);
                Object value = field.get(record);
                if (value != null)
                    cond.put(field.getName(), value);
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        }
        return cond;
    }

    /**
     * 将结果转化为自定义对象
     * @param document
     * @param target
     * @param <Q>
     * @return
     */
    private <Q> Q parseToObject(Document document, Class<Q> target) {
        try {
            Q result = target.newInstance();
            Field[] fields = target.getDeclaredFields();
            for (Field f : fields) {
                f.setAccessible(true);
                Object value = document.get(f.getName());
                if (value == null)
                    continue;
                else if (f.getType() == Integer.class)
                    f.set(result, ((Number) value).intValue());
                else if (f.getType() == Long.class)
                    f.set(result, ((Number) value).longValue());
                else
                    f.set(result, document.get(f.getName(), f.getType()));
            }
            return result;
        } catch (IllegalAccessException e) {
            e.printStackTrace();
            return null;
        } catch (InstantiationException e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 使id自增
     * @param records
     * @param 
     * @return
     */
    private  boolean changeIds(List records) {
        if (records == null || records.size() == 0)
            return false;
        Class clazz = records.get(0).getClass();
        try {
            Field id = clazz.getDeclaredField("id");
            id.setAccessible(true);
            int top = getTop();
            for (Q record: records) {
                id.set(record,++top);
            }
        } catch (NoSuchFieldException e) {
            e.printStackTrace();
            return false;
        } catch (IllegalAccessException e) {
            e.printStackTrace();
            return false;
        }
        return true;
    }

    /**
     * 查找顶针
     * @return
     */
    private int getTop() {
        return ((Number) thisCollection().find().sort(new BasicDBObject("id",-1)).first().get("id")).intValue();
    }

}

Related articles:

java operation mongodb: basic addition, deletion, modification and query

MongoDB (6) java operation mongodb addition, deletion, modification and query

Related videos:

Black Horse Cloud Classroom mongodb practical video tutorial

The above is the detailed content of Java implements mongodb, generic encapsulation, addition, deletion, query, modification, conditional query and other operations. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
How does IntelliJ IDEA identify the port number of a Spring Boot project without outputting a log?How does IntelliJ IDEA identify the port number of a Spring Boot project without outputting a log?Apr 19, 2025 pm 11:45 PM

Start Spring using IntelliJIDEAUltimate version...

How to elegantly obtain entity class variable names to build database query conditions?How to elegantly obtain entity class variable names to build database query conditions?Apr 19, 2025 pm 11:42 PM

When using MyBatis-Plus or other ORM frameworks for database operations, it is often necessary to construct query conditions based on the attribute name of the entity class. If you manually every time...

How to use the Redis cache solution to efficiently realize the requirements of product ranking list?How to use the Redis cache solution to efficiently realize the requirements of product ranking list?Apr 19, 2025 pm 11:36 PM

How does the Redis caching solution realize the requirements of product ranking list? During the development process, we often need to deal with the requirements of rankings, such as displaying a...

How to safely convert Java objects to arrays?How to safely convert Java objects to arrays?Apr 19, 2025 pm 11:33 PM

Conversion of Java Objects and Arrays: In-depth discussion of the risks and correct methods of cast type conversion Many Java beginners will encounter the conversion of an object into an array...

How do I convert names to numbers to implement sorting and maintain consistency in groups?How do I convert names to numbers to implement sorting and maintain consistency in groups?Apr 19, 2025 pm 11:30 PM

Solutions to convert names to numbers to implement sorting In many application scenarios, users may need to sort in groups, especially in one...

E-commerce platform SKU and SPU database design: How to take into account both user-defined attributes and attributeless products?E-commerce platform SKU and SPU database design: How to take into account both user-defined attributes and attributeless products?Apr 19, 2025 pm 11:27 PM

Detailed explanation of the design of SKU and SPU tables on e-commerce platforms This article will discuss the database design issues of SKU and SPU in e-commerce platforms, especially how to deal with user-defined sales...

How to set the default run configuration list of SpringBoot projects in Idea for team members to share?How to set the default run configuration list of SpringBoot projects in Idea for team members to share?Apr 19, 2025 pm 11:24 PM

How to set the SpringBoot project default run configuration list in Idea using IntelliJ...

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

Powerful PHP integrated development environment

mPDF

mPDF

mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

MinGW - Minimalist GNU for Windows

MinGW - Minimalist GNU for Windows

This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools