Comprehensive guide for querying and modifying JCR repository nodes and properties.

Hướng dẫn Truy vấn & Sửa đổi JCR

Tổng quan: 3 Cách Query JCR trong AEM

Phương pháp	Khi nào dùng	Ưu điểm	Nhược điểm
QueryBuilder API	Query phức tạp, có input từ user	Tự động sanitize, dễ maintain	Cú pháp dài hơn
SQL2 (JCR-SQL2)	Query đơn giản, performance cao	Cú pháp giống SQL, nhanh	Cần tự handle injection
JCR Session API	Thao tác CRUD node trực tiếp	Control toàn bộ JCR	Dễ leak session, verbose

1. QueryBuilder API

import com.day.cq.search.PredicateGroup;
import com.day.cq.search.Query;
import com.day.cq.search.QueryBuilder;
import com.day.cq.search.result.Hit;
import com.day.cq.search.result.SearchResult;
import org.apache.sling.api.SlingHttpServletRequest;
import org.osgi.service.component.annotations.Reference;
import javax.jcr.Session;
import java.util.*;

public class MyQueryBuilderService {

    @Reference
    private QueryBuilder queryBuilder;

    public List<Hit> executeCustomQuery(SlingHttpServletRequest request, String locale) {
        Session session = request.getResourceResolver().adaptTo(Session.class);
        if (session == null) return Collections.emptyList();

        Map<String, String> predicates = new HashMap<>();
        predicates.put("path", "/content/experience-fragments");
        predicates.put("type", "nt:unstructured");

        predicates.put("group.p.or", "false");
        predicates.put("group.1_property", "sling:resourceType");
        predicates.put("group.1_property.value", "myproject/components/testModel");
        predicates.put("group.2_property", "jcr:content/@locale");
        predicates.put("group.2_property.value", locale.toLowerCase());

        predicates.put("p.offset", "0");
        predicates.put("p.limit", "-1");
        predicates.put("p.hits", "full");

        Query query = queryBuilder.createQuery(PredicateGroup.create(predicates), session);
        SearchResult result = query.getResult();
        return result.getHits();
    }
}

Lưu ý: Tránh p.limit="-1" trong production với dataset lớn — dùng pagination thay thế.

2. SQL2 Query

import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ResourceResolver;
import javax.jcr.query.Query;
import java.util.Iterator;

public class Sql2QueryExample {

    // Cách 1: Sanitize input trước khi concatenate
    public Iterator<Resource> findResourcesByLocale(ResourceResolver resolver, String locale, String resourceType) {
        String safeLocale = locale.replaceAll("[^a-zA-Z0-9_-]", "");
        String safeResourceType = resourceType.replaceAll("[^a-zA-Z0-9/:_-]", "");

        String sql2 = String.format(
            "SELECT * FROM [nt:unstructured] AS s " +
            "WHERE ISDESCENDANTNODE([/content/experience-fragments]) " +
            "AND [sling:resourceType] = '%s' " +
            "AND LOWER([jcr:content/@locale]) = '%s' " +
            "ORDER BY [jcr:created] DESC",
            safeResourceType, safeLocale.toLowerCase()
        );

        return resolver.findResources(sql2, Query.JCR_SQL2);
    }

    // Cách 2: Bind variables (AEM 6.5 SP10+)
    public Iterator<Resource> findWithBindVars(ResourceResolver resolver, String locale) {
        String sql2 = "SELECT * FROM [nt:unstructured] AS s " +
                      "WHERE ISDESCENDANTNODE([/content/myproject]) " +
                      "AND [jcr:content/@locale] = $locale";

        Map<String, Object> bindings = new HashMap<>();
        bindings.put("locale", locale.toLowerCase());

        return resolver.findResources(sql2, Query.JCR_SQL2, bindings);
    }
}

3. JCR Session API

import org.apache.sling.api.resource.ResourceResolver;
import org.apache.sling.api.resource.ResourceResolverFactory;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import javax.jcr.Node;
import javax.jcr.Session;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

@Component(service = JcrContentService.class)
public class JcrContentService {

    @Reference
    private ResourceResolverFactory resolverFactory;

    private static final String SERVICE_USER = "myproject-content-service";

    public void storeContent(String contentPath, String message) {
        Map<String, Object> params = new HashMap<>();
        params.put(ResourceResolverFactory.SUBSERVICE, SERVICE_USER);

        try (ResourceResolver resolver = resolverFactory.getServiceResourceResolver(params)) {
            Session session = resolver.adaptTo(Session.class);
            if (session == null) return;

            Node root = session.getRootNode();
            Node adobe = root.hasNode("adobe") ? root.getNode("adobe") : root.addNode("adobe");
            Node day = adobe.hasNode("day") ? adobe.getNode("day") : adobe.addNode("day");

            day.setProperty("message", message);
            day.setProperty("jcr:lastModified", Calendar.getInstance());

            session.save();

        } catch (Exception e) {
            org.slf4j.LoggerFactory.getLogger(JcrContentService.class)
                .error("Failed to store content at {}", contentPath, e);
        }
    }

    public String retrieveContent(String nodePath) {
        Map<String, Object> params = Collections.singletonMap(
            ResourceResolverFactory.SUBSERVICE, SERVICE_USER);

        try (ResourceResolver resolver = resolverFactory.getServiceResourceResolver(params)) {
            Session session = resolver.adaptTo(Session.class);
            if (session == null) return null;

            if (session.nodeExists(nodePath)) {
                Node node = session.getNode(nodePath);
                return node.hasProperty("message")
                    ? node.getProperty("message").getString()
                    : null;
            }
            return null;

        } catch (Exception e) {
            org.slf4j.LoggerFactory.getLogger(JcrContentService.class)
                .error("Failed to retrieve content from {}", nodePath, e);
            return null;
        }
    }
}

Cấu hình Service User

org.apache.sling.serviceusermapping.impl.ServiceUserMapperImpl.amended-myproject.cfg

user.mapping=[ \
    "myproject:content-service=[myproject-content-service]" \
]

org.apache.sling.serviceusermapping.impl.ServiceUserMapperImpl.amended-myproject.cfg.json

{
  "user.mapping": [
    "myproject:content-service=[myproject-content-service]"
  ]
}

4. Groovy Console Scripts

SQL2 Query

import javax.jcr.query.Query

def buildSafeQuery(pagePath, resourceType) {
    def safePath = pagePath.replaceAll(/['\\]/, '')
    def safeType = resourceType.replaceAll(/['\\]/, '')

    def statement = "SELECT * FROM [nt:unstructured] WHERE " +
                    "ISDESCENDANTNODE(['${safePath}']) AND " +
                    "[sling:resourceType] = '${safeType}'"

    session.workspace.queryManager.createQuery(statement, Query.JCR_SQL2)
}

def query = buildSafeQuery('/content/geometrixx/en', 'geometrixx/components/contentpage')
def result = query.execute()

result.nodes.each { node ->
    println node.path
}

Delete Property

import javax.jcr.query.Query

def statement = "/jcr:root/content/eurowings//*[@jcr:language]"
def query = session.workspace.queryManager.createQuery(statement, Query.XPATH)
def result = query.execute()
def deletedCount = 0

result.nodes.each { node ->
    if (node.path.contains('/backoffice/') && node.hasProperty('jcr:language')) {
        node.getProperty('jcr:language').remove()
        deletedCount++
    }
}

if (deletedCount > 0) {
    session.save()
    println "Saved: ${deletedCount} properties deleted"
} else {
    println "No changes made"
}

Lưu ý: Gọi session.save() một lần sau loop, không save trong từng iteration.

5. Delete Inbox Notifications

public void cleanupInboxTasks(ResourceResolver resolver, String taskPrefix) {
    Resource tasksRoot = resolver.getResource("/var/taskmanagement/tasks");
    if (tasksRoot == null) return;

    tasksRoot.listChildren().forEachRemaining(task -> {
        if (task.getName().startsWith(taskPrefix)) {
            try {
                resolver.delete(task);
                log.info("Deleted task: {}", task.getPath());
            } catch (PersistenceException e) {
                log.error("Failed to delete task: {}", task.getPath(), e);
            }
        }
    });

    resolver.commit();
}

Cheat Sheet: Query Patterns AEM 6.5

// QueryBuilder: Tìm component theo resourceType + property
predicates.put("type", "nt:unstructured");
predicates.put("path", "/content/myproject");
predicates.put("1_property", "sling:resourceType");
predicates.put("1_property.value", "myproject/components/hero");
predicates.put("2_property", "jcr:content/@published");
predicates.put("2_property.operation", "exists");

// SQL2: Tìm page theo template + language
"SELECT * FROM [cq:Page] AS p " +
"WHERE ISDESCENDANTNODE([/content/myproject]) " +
"AND [jcr:content/cq:template] = '/conf/myproject/settings/wcm/templates/landing' " +
"AND [jcr:language] = 'vi'"

// XPath (tránh dùng nếu có thể):
"/jcr:root/content/myproject//element(*, cq:Page)[@jcr:language='vi']"

// Fulltext search:
predicates.put("fulltext", "keyword");
predicates.put("fulltext.relPath", "jcr:content");

Common Pitfalls & Fixes

Lỗi	Nguyên nhân	Fix
`QueryFormatException`	Input chưa escape trong SQL2	Dùng bind variables hoặc sanitize input
`LoginException`	Service user chưa config	Kiểm tra `ServiceUserMapperImpl` config
Query chậm	Thiếu index, query quá rộng	Tạo Oak index, thêm `p.limit`, filter path
Memory leak	Không close ResourceResolver	Dùng try-with-resources
Save không effect	Quên `session.save()` hoặc `resolver.commit()`	Commit sau khi modify
Permission denied	Service user thiếu ACL	Grant permission qua `rep:policy` node

Performance Tips

Tạo Oak index cho property thường query tại /oak:index
Luôn set p.limit hoặc dùng cursor-based pagination
Tránh ISDESCENDANTNODE([/]) — luôn chỉ định path cụ thể
Với query nặng, dùng JobManager để chạy background

{
  "jcr:primaryType": "oak:QueryIndexDefinition",
  "type": "property",
  "propertyNames": ["sling:resourceType"],
  "declaringNodeTypes": ["nt:unstructured"]
}

#Hướng dẫn Truy vấn & Sửa đổi JCR

#Tổng quan: 3 Cách Query JCR trong AEM

#1. QueryBuilder API

#2. SQL2 Query

#3. JCR Session API

#Cấu hình Service User

#4. Groovy Console Scripts

#SQL2 Query

#Delete Property

#5. Delete Inbox Notifications

#Cheat Sheet: Query Patterns AEM 6.5

#Common Pitfalls & Fixes

#Performance Tips