How to Build a Basic CRUD App with Java?

introduction in this guide, you'll learn to create a full featured crud (create, read, update, delete) application using java we will leverage back4app as the backend service to manage your data effortlessly this tutorial demonstrates the core functionalities of a crud system, showing you how to set up a back4app project, design a flexible data model, and implement crud operations with a java application initially, you'll configure a back4app project called basic crud app java which provides a robust non relational data storage environment for your application you will define your data model by creating classes and fields manually or with the assistance of back4app's ai agent following that, you will manage your backend using the back4app admin app, a user friendly drag and drop interface for data manipulation finally, you'll integrate your java application with back4app using the parse java sdk (or rest/graphql where needed) while implementing secure access controls by the end of this tutorial, you'll have developed a production ready java application that performs basic crud operations, including secure user authentication and data management key takeaways discover how to build a java based crud application with an efficient non relational backend gain insights into structuring a scalable backend and integrating it with a java application learn how to use back4app’s intuitive admin app to streamline create, read, update, and delete operations explore deployment strategies, including docker containerization, to deploy your java application seamlessly prerequisites before starting, ensure you have a back4app account with a new project configured need assistance? check out getting started with back4app https //www back4app com/docs/get started/new parse app a java development environment use an ide like intellij idea or eclipse make sure you have java 11 (or newer) installed familiarity with java, object oriented programming, and rest apis review the java documentation https //docs oracle com/en/java/ if necessary step 1 – project setup creating a new back4app project sign in to your back4app account click the “new app” button on your dashboard enter the project name basic crud app java and follow the prompts to finalize project creation create new project once your project is created, it will be listed on your dashboard, providing the groundwork for your backend configuration step 2 – designing the data model configuring your data structures for this crud application, you will define several classes (collections) in your back4app project the following examples outline the key classes and their fields necessary to support basic crud operations 1\ items class this class holds details about each item field data type description id objectid automatically generated unique identifier title string the name of the item description string a short summary of the item createdat date timestamp when the item was created updatedat date timestamp when the item was last modified 2\ users class this class manages user credentials and authentication details field data type description id objectid auto generated unique identifier username string unique identifier for the user email string unique email address passwordhash string encrypted password for authentication createdat date timestamp when the account was created updatedat date timestamp when the account was updated you can manually create these classes and define fields in the back4app dashboard create new class you can add fields by selecting a data type, specifying the field name, assigning a default value, and indicating if it is mandatory create column leveraging the back4app ai agent for schema setup the back4app ai agent is a smart tool integrated into your dashboard that can automatically generate your data schema based on your description this feature streamlines project setup and ensures that your data model supports the necessary crud operations steps to use the ai agent access the ai agent log in to your back4app dashboard and locate the ai agent under your project settings describe your data model provide a detailed prompt outlining the classes and fields required review and apply after processing, the ai agent will propose the schema setup review the details and confirm to implement the configuration sample prompt create the following classes in my back4app project 1\) class items \ fields \ id objectid (auto generated) \ title string \ description string \ createdat date (auto generated) \ updatedat date (auto updated) 2\) class users \ fields \ id objectid (auto generated) \ username string (unique) \ email string (unique) \ passwordhash string \ createdat date (auto generated) \ updatedat date (auto updated) this ai driven approach saves time and guarantees a consistent, optimized data model for your application step 3 – activating the admin app & managing crud operations introduction to the admin app the back4app admin app offers a no code interface for efficient backend data management its intuitive drag and drop functionality simplifies performing crud operations like creating, viewing, updating, and removing records activating the admin app navigate to the “more” menu in your back4app dashboard select “admin app” and then click on “enable admin app ” set up your admin credentials by creating your initial admin account this process will also establish roles (such as b4aadminuser ) and system classes enable admin app once enabled, log in to the admin app to manage your application data admin app dashboard utilizing the admin app for crud tasks within the admin app, you can add records use the “add record” option within a class (for example, items) to insert new data view/modify records click on any record to examine details or edit fields remove records delete entries that are no longer necessary this streamlined interface enhances user experience by simplifying data management step 4 – integrating your java application with back4app with your backend configured, the next step is to connect your java application to back4app option a using the parse java sdk add the parse java sdk dependency if you're using maven, include the following in your pom xml \<dependency> \<groupid>com parse\</groupid> \<artifactid>parse sdk\</artifactid> \<version>1 18 0\</version> \</dependency> initialize parse in your java application create a configuration class (e g , parseconfig java ) // parseconfig java import com parse parse; public class parseconfig { public static void initialize() { parse initialize(new parse configuration builder("your application id") clientkey("your java key") server("https //parseapi back4app com") build()); } } implement crud operations in a java class for instance, create a service to fetch and display items // itemsservice java import com parse parseexception; import com parse parseobject; import com parse parsequery; import java util list; public class itemsservice { public list\<parseobject> getitems() { parsequery\<parseobject> query = parsequery getquery("items"); try { return query find(); } catch (parseexception e) { system err println("failed to fetch items " + e getmessage()); return null; } } public void createitem(string title, string description) { parseobject item = new parseobject("items"); item put("title", title); item put("description", description); try { item save(); system out println("item created successfully "); } catch (parseexception e) { system err println("error creating item " + e getmessage()); } } public void updateitem(string objectid, string newtitle, string newdescription) { parsequery\<parseobject> query = parsequery getquery("items"); try { parseobject item = query get(objectid); item put("title", newtitle); item put("description", newdescription); item save(); system out println("item updated successfully "); } catch (parseexception e) { system err println("error updating item " + e getmessage()); } } public void deleteitem(string objectid) { parsequery\<parseobject> query = parsequery getquery("items"); try { parseobject item = query get(objectid); item delete(); system out println("item deleted successfully "); } catch (parseexception e) { system err println("error deleting item " + e getmessage()); } } } option b using rest or graphql if the parse java sdk is not an option, you can perform crud operations via rest calls for example, to fetch items using rest import java io bufferedreader; import java io inputstreamreader; import java net httpurlconnection; import java net url; public class restclient { public static void fetchitems() { try { url url = new url("https //parseapi back4app com/classes/items"); httpurlconnection conn = (httpurlconnection) url openconnection(); conn setrequestmethod("get"); conn setrequestproperty("x parse application id", "your application id"); conn setrequestproperty("x parse rest api key", "your rest api key"); bufferedreader in = new bufferedreader(new inputstreamreader(conn getinputstream())); string inputline; stringbuilder response = new stringbuilder(); while ((inputline = in readline()) != null) { response append(inputline); } in close(); system out println("response " + response tostring()); } catch (exception e) { system err println("error fetching items " + e getmessage()); } } } integrate these api calls into your java classes as needed step 5 – securing your backend access control lists (acls) protect your data by configuring acls for your objects for example, to create an item visible only to its owner import com parse parseacl; import com parse parseuser; public void createprivateitem(string title, string description, parseuser owner) { parseobject item = new parseobject("items"); item put("title", title); item put("description", description); parseacl acl = new parseacl(); acl setreadaccess(owner, true); acl setwriteaccess(owner, true); acl setpublicreadaccess(false); acl setpublicwriteaccess(false); item setacl(acl); try { item save(); system out println("private item created "); } catch (parseexception e) { system err println("error saving item " + e getmessage()); } } class level permissions (clps) configure clps in your back4app dashboard to enforce default access rules this setup ensures that only authenticated users can access specific classes step 6 – implementing user authentication configuring user accounts back4app uses parse’s built in user class for managing authentication in your java application, manage user registration and login as shown below import com parse parseexception; import com parse parseuser; public class authservice { public void signup(string username, string password, string email) { parseuser user = new parseuser(); user setusername(username); user setpassword(password); user setemail(email); try { user signup(); system out println("user successfully registered!"); } catch (parseexception e) { system err println("sign up error " + e getmessage()); } } public void login(string username, string password) { try { parseuser user = parseuser login(username, password); system out println("user logged in " + user getusername()); } catch (parseexception e) { system err println("login failed " + e getmessage()); } } } a similar approach can be applied for session management, password resets, and additional authentication features step 7 – deploying your java application back4app offers a streamlined deployment process you can deploy your java application using various methods, including docker containerization 7 1 building your java application compile and package use your build tool (such as maven or gradle) to compile and package your application for maven, run mvn clean package verify the package ensure that the generated jar file contains all necessary classes and resources 7 2 organize your project structure a typical java project structure may resemble basic crud app java/ \| src/ \| | main/ \| | java/ \| | com/ \| | yourdomain/ \| | app java \| | parseconfig java \| | services/ \| | itemsservice java \| | authservice java \| | resources/ \| | application properties \| pom xml \| readme md example parseconfig java // parseconfig java import com parse parse; public class parseconfig { public static void initialize() { parse initialize(new parse configuration builder("your application id") clientkey("your java key") server("https //parseapi back4app com") build()); } } 7 3 dockerizing your java application if you opt for containerized deployment, include a dockerfile in your project root \# use an openjdk image as the base from openjdk 11 jre slim \# set the working directory workdir /app \# copy the packaged jar into the container copy target/basic crud app java jar app jar \# expose the port (adjust if needed) expose 8080 \# run the application entrypoint \["java", " jar", "app jar"] 7 4 deploying with back4app web deployment link your github repository ensure your java project's source code is hosted on github configure deployment settings in your back4app dashboard, select the web deployment feature, link your repository (e g , basic crud app java ), and choose the appropriate branch set build and output commands define the build command (e g , mvn clean package ) and specify the artifact location deploy your application click deploy and monitor the deployment logs until your app is live step 8 – conclusion and next steps congratulations! you've successfully built a java based crud application integrated with back4app you set up a project named basic crud app java , designed classes for items and users, and managed your data using the back4app admin app additionally, you connected your java application via the parse sdk (or rest/graphql) and implemented robust security measures next steps enhance the application add more features such as advanced search, detailed views, or real time updates extend backend functionality explore cloud functions, third party api integrations, or role based access controls deepen your knowledge check out the back4app documentation https //www back4app com/docs and additional tutorials to further optimize your app happy coding and best of luck with your java crud application!