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java将字符串存入GridF并通过id或文件名查询

import static org.bson.codecs.configuration.CodecRegistries.fromProviders;import static org.bson.codecs.configuration.CodecRegistries.fromRegistries;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.InputStream;import java.util.ArrayList;import java.util.List;import org.bson.codecs.configuration.CodecProvider;import org.bson.codecs.configuration.CodecRegistry;import org.bson.codecs.pojo.PojoCodecProvider;import org.bson.types.ObjectId;import com.mongodb.MongoClient;import com.mongodb.MongoClientOptions;import com.mongodb.MongoCredential;import com.mongodb.ServerAddress;import com.mongodb.client.MongoDatabase;import com.mongodb.client.gridfs.GridFSBucket;import com.mongodb.client.gridfs.GridFSBuckets;public class Test {    private MongoDatabase database = null;    public static void main(String[] args) throws Exception {        Test t=new Test();        String ID = t.insertMedicalFile("测试一下1.txt", "fjkasdhfkjhdaslfhklahflasdhlhflk");        String selectMedicalFileByObjectId = t.selectMedicalFileByObjectId("5c91ec501a551431b07eff28");        String selectMedicalFileByFileName = t.selectMedicalFileByFileName("测试一下1.txt");    }        /**     * 向 IMAGE_FILE 中写入文件记录。     * @param fileName  文件名     * @param xmlContent   文件内容。     * @throws Exception     */    public String  insertMedicalFile(String fileName , String xmlContent) throws Exception{        MongoDatabase mds = null;        mds = getMdbOperator();        InputStream inputStream = new ByteArrayInputStream(xmlContent.getBytes("UTF-8"));        //业务逻辑模式        GridFSBucket gridFSBucket = GridFSBuckets.create(mds,"IMAGE_FILE");        ObjectId objectId = gridFSBucket.uploadFromStream(fileName, inputStream);        System.out.println("HUC 生成的 objectId  = " + objectId);                inputStream.close();                return objectId+"" ;    }    /**     * 根据文件id返回文件内容     * @param objectId     * @return     */    public String selectMedicalFileByObjectId(String objectId){        String result = "" ;        try {            MongoDatabase mds = null;            mds = getMdbOperator();            GridFSBucket gridFSBucket = GridFSBuckets.create(mds,"IMAGE_FILE");                        ByteArrayOutputStream baos = new ByteArrayOutputStream();               gridFSBucket.downloadToStream(new ObjectId(objectId), baos);                        result =  baos.toString("UTF-8");                    } catch (Exception e) {            result = "" ; //此处可能会报异常错误,异常错误的原因是 上面 downloadToStream 为空。            e.printStackTrace();        }        return result ;     }    /**     * 根据文件名返回文件内容     * @param fileName     * @return     */    public String selectMedicalFileByFileName(String fileName){        String result = "" ;        try {            MongoDatabase mds = null;            mds = getMdbOperator();            GridFSBucket gridFSBucket = GridFSBuckets.create(mds,"IMAGE_FILE");                        ByteArrayOutputStream baos = new ByteArrayOutputStream();               gridFSBucket.downloadToStream(fileName, baos);                        result =  baos.toString("UTF-8");                    } catch (Exception e) {            result = "" ; //此处可能会报异常错误,异常错误的原因是 上面 downloadToStream 为空。            e.printStackTrace();        }        return result ;     }    /**     * 获得链接     *      * @return     */    public MongoDatabase getMdbOperator() {        try {            MongoClient mongoClient = getMongoClient();            if (mongoClient != null) {                CodecProvider pojoCodecProvider = PojoCodecProvider.builder()                        .automatic(true).build();                CodecRegistry pojoCodecRegistry = fromRegistries(                        MongoClient.getDefaultCodecRegistry(),                        fromProviders(pojoCodecProvider));                database = mongoClient.getDatabase("HUC")                        .withCodecRegistry(pojoCodecRegistry);                return database;            } else {            }        } catch (Exception e) {            e.printStackTrace();        }        return null;    }            private static MongoClient getMongoClient() throws Exception {        MongoClientOptions.Builder build = new MongoClientOptions.Builder();        // 与目标数据库能够建立的最大connection数量为200,当连接池被用光时,会被阻塞住        build.connectionsPerHost(200);        // 如果当前所有的connection都在使用中,则每个connection上可以有100个线程排队等待        build.threadsAllowedToBlockForConnectionMultiplier(100);        /*         * 一个线程访问数据库的时候,在成功获取到一个可用数据库连接之前的最长等待时间为2分钟         * 这里比较危险,如果超过maxWaitTime都没有获取到这个连接的话,该线程就会抛出Exception         * 故这里设置的maxWaitTime应该足够大,以免由于排队线程过多造成的数据库访问失败         */        build.maxWaitTime(1000 * 60 * 2); // 这个就是Server Selection                                            // Timeout?        build.connectTimeout(1000 * 60 * 1); // 与数据库建立连接的timeout设置为1分钟        build.socketTimeout(10 * 1000); // 发送请求和接收请求的超时时间        MongoClientOptions myOptions = build.build();        // 创建链接        MongoCredential credential = MongoCredential.createCredential(                "admin", "HUC", "123456".toCharArray());        List addresses = new ArrayList();        //mongoDB集群地址        addresses.add(new ServerAddress("192.168.220.130", 27017));        addresses.add(new ServerAddress("192.168.220.128", 27017));        addresses.add(new ServerAddress("192.168.220.129", 27017));        return new MongoClient(addresses,credential,myOptions);    }}

 

文章转载于:https://www.cnblogs.com/lm970585581/p/10565669.html

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