CRUD using Spring MVC 4.0 RESTful Web Services and AngularJS

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原文: http://www.tuicool.com/articles/MneeU3f

Based on the requests from many readers, I am now presenting an article on how to make CRUD operations using Spring MVC 4.0 RESTFul web services and AngularJS. I had already written few articles on Spring MVC 4.0 RESTFul Web Services in case you are new to this.

For the sake of best understanding, I came up with a small task manager AngularJS application powered by Spring MVC 4.0 RESTFul Web Services. With this application, you can list all existing tasks, create a new task, mark completion of an existing task and archive completed tasks. I had tried to keep it very simple as this is not for real time use but for the best understanding of the concept.

DEMO DOWNLOAD

Prerequisites

-- MySql Server

-- Eclipse J2EE

-- Tomcat Server v7.0

1. Let us start by creating task table in MySql Server.

Execute the below commands in MySql Server. This will create a dedicated database for our application and will create a task_list table with dummy values to start with initially,

use taskmanager;
create table task_list(task_id int not null auto_increment, task_name varchar(100) not null, task_description text,task_priority varchar(20),task_status varchar(20),task_start_time datetime not null,task_end_time datetime not null,task_archived bool default false,primary key(task_id));
insert into task_list values(1,'Gathering Requirement','Requirement Gathering','MEDIUM','ACTIVE',curtime(),curtime() + INTERVAL 3 HOUR,0);
insert into task_list values(2,'Application Designing','Application Designing','MEDIUM','ACTIVE',curtime(),curtime() + INTERVAL 2 HOUR,0);
insert into task_list values(3,'Implementation','Implementation','MEDIUM','ACTIVE',curtime(),curtime() + INTERVAL 3 HOUR,0);
insert into task_list values(4,'Unit Testing','Unit Testing','LOW','ACTIVE',curtime(),curtime() + INTERVAL 4 HOUR,0);
insert into task_list values(5,'Maintanence','Maintanence','LOW','ACTIVE',curtime(),curtime() + INTERVAL 5 HOUR,0);
select * from task_list;

2.  Download

        -- Spring MVC 4.0 jar files from this maven repository  here

.

        --  Download latest version of jackson json library from  her e

             (1) jackson-annotations-x.x.x.jar

             (2) jackson-core-x.x.x.jar

             (3) jackson-databind-x.x.x.jar

        -- Download mysql java connector library.

3. Create a dynamic web project in eclipse and add the above downloaded jar files to your application WEN-INF\lib folder.

4. Now edit web.xml file under WebContent folder to notify the application container about the spring configuration file. Add below code before </web-app>

<servlet>
 <servlet-name>rest</servlet-name>
 <servlet-class>
  org.springframework.web.servlet.DispatcherServlet
 </servlet-class>
 <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
 <servlet-name>rest</servlet-name>
 <url-pattern>/*</url-pattern>
</servlet-mapping>

Note that in the above code,we have named Spring Dispatcher servlet class as "rest" and the url pattern is given as "/*" which means any uri with the root of this web application will call DispatcherServlet. So what's next? DispatcherServlet will look for configuration files following this naming convention -  [servlet-name]-servlet.xml . In this example, I have named dispatcher servlet class as "rest" and hence it will look for file named 'rest-servlet.xml'.

5. Create a file under WEB-INF folder and name it as "rest-servlet.xml". Add below spring configuration code to it,

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:context="http://www.springframework.org/schema/context"
 xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns:p="http://www.springframework.org/schema/p"
 xsi:schemaLocation="
   http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
   http://www.springframework.org/schema/context
   http://www.springframework.org/schema/context/spring-context-4.0.xsd
   http://www.springframework.org/schema/mvc
   http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">
 <context:component-scan base-package="com.programmingfree.springservice.controller" />
 <mvc:annotation-driven />
 </beans>

I have already explained component-scan element and mvc:annotation-driven element in my previous article, so I am not going to repeat it here again.

6. Create a Java class and name it "Task.java". This is the model class and it represents the fields of a single task in the database.

package com.programmingfree.springservice.domain;

public class Task {

 private int task_id;
  private String task_name;
  private String task_description;
  private String task_priority;
  private String task_status;

  public int getTaskId() {
   return task_id;
  }
  public void setTaskId(int taskId) {
   this.task_id = taskId;
  }
  public String getTaskName() {
   return task_name;
  }
  public void setTaskName(String taskName) {
   this.task_name = taskName;
  }
  public String getTaskDescription() {
   return task_description;
  }
  public void setTaskDescription(String taskDescription) {
   this.task_description = taskDescription;
  }

  public String getTaskPriority() {
   return task_priority;
  }
  public void setTaskPriority(String taskPriority) {
   this.task_priority = taskPriority;
  }

  public String getTaskStatus() {
   return task_status;
  }

 public void setTaskStatus(String taskStatus) {
   this.task_status = taskStatus;
  }

  @Override
  public String toString() {
   return "Task [task_id=" + task_id + ", task_name=" + task_name
     + ", task_description=" + task_description + ", task_priority="
     + task_priority +",task_status="+task_status+ "]";
  }

}

7. Create a utility class to handle connections to database. The connection string properties are kept in a configuration file called "db.properties" in the src folder.

package com.programmingfree.springservice.utility;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

public class DBUtility {
 private static Connection connection = null;

  public static Connection getConnection() {
    if (connection != null)
      return connection;
    else {
      try {
       Properties prop = new Properties();
        InputStream inputStream = DBUtility.class.getClassLoader().getResourceAsStream("/config.properties");
        prop.load(inputStream);
        String driver = prop.getProperty("driver");
        String url = prop.getProperty("url");
        String user = prop.getProperty("user");
        String password = prop.getProperty("password");
        Class.forName(driver);
        connection = DriverManager.getConnection(url, user, password);
      } catch (ClassNotFoundException e) {
        e.printStackTrace();
      } catch (SQLException e) {
        e.printStackTrace();
      } catch (FileNotFoundException e) {
        e.printStackTrace();
      } catch (IOException e) {
        e.printStackTrace();
      }
      return connection;
    }

  }

}

Properties configuration file should have contents such as this,

driver=com.mysql.jdbc.Driver

url=jdbc:mysql://localhost:3306/databasename

user=username

password=xxxxxx

8. Create a service class that performs data access operations to get data from database,

package com.programmingfree.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import com.programmingfree.springservice.domain.*;
import com.programmingfree.springservice.utility.DBUtility;
public class TaskManagerService {

 private Connection connection;

 public TaskManagerService() {
  connection = DBUtility.getConnection();
 }

 public void addTask(Task task) {
  try {
   PreparedStatement preparedStatement = connection
     .prepareStatement("insert into task_list(task_name,task_description,task_priority,task_status,task_archived,task_start_time,task_end_time) values (?, ?, ?,?,?,?,?)");
   System.out.println("Task:"+task.getTaskName());
   preparedStatement.setString(1, task.getTaskName());
   preparedStatement.setString(2, task.getTaskDescription());
   preparedStatement.setString(3, task.getTaskPriority());
   preparedStatement.setString(4, task.getTaskStatus());
   preparedStatement.setInt(5,0);
   Date dt = new Date();

   SimpleDateFormat sdf =
        new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

   String currentTime = sdf.format(dt);
   preparedStatement.setString(6,currentTime);
   preparedStatement.setString(7,currentTime);
   preparedStatement.executeUpdate();

  } catch (SQLException e) {
   e.printStackTrace();
  }
 }

 public void archiveTask(int taskId) {
  try {
   PreparedStatement preparedStatement = connection
     .prepareStatement("update task_list set task_archived=true where task_id=?");
   // Parameters start with 1
   preparedStatement.setInt(1, taskId);
   preparedStatement.executeUpdate();

  } catch (SQLException e) {
   e.printStackTrace();
  }
 }

 public void updateTask(Task task) throws ParseException {
  try {
   PreparedStatement preparedStatement = connection
     .prepareStatement("update task_list set task_name=?, task_description=?, task_priority=?,task_status=?" +
       "where task_id=?");
   preparedStatement.setString(1, task.getTaskName());
   preparedStatement.setString(2, task.getTaskDescription());

   preparedStatement.setString(3, task.getTaskPriority());
   preparedStatement.setString(4, task.getTaskStatus());
   preparedStatement.setInt(4, task.getTaskId());
   preparedStatement.executeUpdate();

  } catch (SQLException e) {
   e.printStackTrace();
  }
 }

 public void changeTaskStatus(int taskId,String status) throws ParseException {
   try {
    PreparedStatement preparedStatement = connection
      .prepareStatement("update task_list set task_status=? where task_id=?");
    preparedStatement.setString(1,status);
    preparedStatement.setInt(2, taskId);
    preparedStatement.executeUpdate();

   } catch (SQLException e) {
    e.printStackTrace();
   }
  }

 public List<task> getAllTasks() {
  List<task> tasks = new ArrayList<task>();
  try {
   Statement statement = connection.createStatement();
   ResultSet rs = statement.executeQuery("select * from task_list where task_archived=0");
   while (rs.next()) {
    Task task = new Task();
    task.setTaskId(rs.getInt("task_id"));
    task.setTaskName(rs.getString("task_name"));
    task.setTaskDescription(rs.getString("task_description"));
    task.setTaskPriority(rs.getString("task_priority"));
    task.setTaskStatus(rs.getString("task_status"));
    tasks.add(task);
   }
  } catch (SQLException e) {
   e.printStackTrace();
  }

  return tasks;
 }

 public Task getTaskById(int taskId) {
  Task task = new Task();
  try {
   PreparedStatement preparedStatement = connection.
     prepareStatement("select * from task_list where task_id=?");
   preparedStatement.setInt(1, taskId);
   ResultSet rs = preparedStatement.executeQuery();

   if (rs.next()) {
     task.setTaskId(rs.getInt("task_id"));
     task.setTaskName(rs.getString("task_name"));
     task.setTaskDescription(rs.getString("task_description"));
     task.setTaskPriority(rs.getString("task_priority"));
     task.setTaskStatus(rs.getString("task_status"));
   }
  } catch (SQLException e) {
   e.printStackTrace();
  }

  return task;
 }
}

9. Create Spring Controller class that maps the incoming request to appropriate methods and returns response in json format. We are going to use @RestController annotation which has @Controller and @Responsebody annotated within itself.

package com.programmingfree.springservice.controller;

import java.text.ParseException;
import java.util.List;

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.programmingfree.dao.TaskManagerService;
import com.programmingfree.springservice.domain.Task;

@RestController
public class TaskManagerController {

 TaskManagerService taskmanagerservice=new TaskManagerService();

  @RequestMapping(value="/tasks",method = RequestMethod.GET,headers="Accept=application/json")
  public List<task> getAllTasks() {
   List<task> tasks=taskmanagerservice.getAllTasks();
   return tasks;

  }

  @RequestMapping(value="/tasks/archive/{taskIds}",method = RequestMethod.POST,headers="Accept=application/json")
  public List<task> archiveAllTasks(@PathVariable int[] taskIds) {
   for(int i=0;i<taskids .length="" ask="" i="" list="" taskids="" taskmanagerservice.archivetask=""> tasks=taskmanagerservice.getAllTasks();
   return tasks;

  }

  @RequestMapping(value="/tasks/{taskId}/{taskStatus}",method = RequestMethod.POST,headers="Accept=application/json")
  public List<task> changeTaskStatus(@PathVariable int taskId,@PathVariable String taskStatus) throws ParseException {
   taskmanagerservice.changeTaskStatus(taskId,taskStatus);
   return taskmanagerservice.getAllTasks();

  }

  @RequestMapping(value="/tasks/insert/{taskName}/{taskDesc}/{taskPriority}/{taskStatus}",method = RequestMethod.POST,headers="Accept=application/json")
  public List<task> addTask(@PathVariable String taskName,@PathVariable String taskDesc,@PathVariable String taskPriority,@PathVariable String taskStatus) throws ParseException {
  Task task = new Task();
  task.setTaskName(taskName);
  task.setTaskDescription(taskDesc);
  task.setTaskPriority(taskPriority);
  task.setTaskStatus(taskStatus);
  taskmanagerservice.addTask(task);
  return taskmanagerservice.getAllTasks();

  }
}

Let us now take a closer look into the methods we have in the Spring Controller class.

-- Initially we use getAllTasks () method to fetch all tasks from database. This will fetch all tasks that are not archived (task_archived = '0').

-- Then we give an option to the user via archiveTasks() method, to archive all completed tasks so that it won't show up on the dashboard. For this purpose, we have a field in task_list table called 'task_archived' with values 0 or 1 marking whether a task is archived or not.

-- An option to update the status of a task from 'ACTIVE' to 'COMPLETED' or vice-versa is provided in the changeStatus() method

-- AddTask() method enables one to add a new task to the database.

10. Let us now create the jsp file that sends requests to the Spring controller to fetch data and to update data in the server,

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html ng-app="taskManagerApp">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>AngularJS Task Manager</title>
<script data-require="angular.js@*" data-semver="1.2.13" src="http://code.angularjs.org/1.2.13/angular.js"></script>
<script type="text/javascript" src="./js/app.js"></script>
</head>
<body>
<div ng-controller="taskManagerController">
 <div id="task-panel" class="fadein fadeout showpanel panel"  ng-show="toggle">
  <div class="panel-heading">
   <i class="panel-title-icon fa fa-tasks"></i>
   <span class="panel-title">Recent Tasks</span>
   <div class="panel-heading-controls">
    <button ng-click="toggle = !toggle" >Add New Task</button>
    <button confirmed-click="archiveTasks()" ng-confirm-click="Would you like to archive completed tasks?">Clear completed tasks</button>
   </div>
  </div>
  <div>
   <div ng-repeat="task in tasks">
    <span>
     {{task.taskPriority}}
    </span>
    <div>
     <input id="{{task.taskId}}" type="checkbox" value="{{task.taskId}}" ng-checked="selection.indexOf(task.taskId) > -1" ng-click="toggleSelection(task.taskId)" />
       <label for="{{task.taskId}}"></label>
    </div>
    <div ng-if="task.taskStatus=='COMPLETED'">
     <a href="#" class="checkedClass">
      {{task.taskName}}
     <span class="action-status">{{task.taskStatus}}</span>
     </a>
    </div>
    <div ng-if="task.taskStatus=='ACTIVE'">
     <a href="#" class="uncheckedClass">
      {{task.taskName}}
      <span class="action-status">{{task.taskStatus}}</span>
     </a>
    </div>
   </div>
  </div>
 </div>
 <div id="add-task-panel" ng-hide="toggle">
  <div>
   <span>Add Task</span>
   <div>
    <button ng-click="toggle = !toggle">Show All Tasks</button>
   </div>
  </div>
  <div>
   <div>
    <table>
     <tr>
      <td>Task Name:</td>
      <td><input type="text" ng-model="taskName"/></td>
     </tr>
     <tr>
      <td>Task Description:</td>
      <td><input type="text" ng-model="taskDesc"/></td>
     </tr>
     <tr>
      <td>Task Status:</td>
      <td>
       <select ng-model="taskStatus" ng-options="status as status for status in statuses">
        <option value="">-- Select --</option>
            </select>
      </td>
     </tr>
     <tr>
      <td>Task Priority:</td>
      <td>
       <select ng-model="taskPriority" ng-options="priority as priority for priority in priorities">
        <option value="">-- Select --</option>
       </select>
      </td>
     </tr>
     <tr>
      <td><br/><button ng-click="addTask()" class="btn-panel-big">Add New Task</button></td>
     </tr>
    </table>
   </div>
  </div>
 </div>
</div>
</body>
</html>

Note that I have not included any styling elements or animations though I have used it in the demonstration to keep the code clean for easy understanding.

11. In the above JSP file, I had referenced a  javascript file called 'app.js' in the head section. Create a file called 'app.js' under WebContent/js folder and copy the below code in it.

var taskManagerModule = angular.module('taskManagerApp', ['ngAnimate']);

taskManagerModule.controller('taskManagerController', function ($scope,$http) {

 var urlBase="http://localhost:8080/TaskManagerApp";
 $scope.toggle=true;
 $scope.selection = [];
 $scope.statuses=['ACTIVE','COMPLETED'];
 $scope.priorities=['HIGH','LOW','MEDIUM'];
 $http.defaults.headers.post["Content-Type"] = "application/x-www-form-urlencoded";

 //get all tasks and display initially
 $http.get(urlBase+'/tasks').
     success(function(data) {
         $scope.tasks = data;
         for(var i=0;i<$scope.tasks.length;i++){
             if($scope.tasks[i].taskStatus=='COMPLETED'){
              $scope.selection.push($scope.tasks[i].taskId);
         }
         }
    });

 //add a new task
 $scope.addTask = function addTask() {
  if($scope.taskName=="" || $scope.taskDesc=="" || $scope.taskPriority == "" || $scope.taskStatus == ""){
   alert("Insufficient Data! Please provide values for task name, description, priortiy and status");
  }
  else{
   $http.post(urlBase + '/tasks/insert/' +$scope.taskName+'/'+$scope.taskDesc+'/'+$scope.taskPriority+'/'+$scope.taskStatus).
    success(function(data) {
    alert("Task added");
    $scope.tasks = data;
    $scope.taskName="";
    $scope.taskDesc="";
    $scope.taskPriority="";
    $scope.taskStatus="";
    $scope.toggle='!toggle';
      });
  }
 };

 // toggle selection for a given task by task id
   $scope.toggleSelection = function toggleSelection(taskId) {
     var idx = $scope.selection.indexOf(taskId);

     // is currently selected
     if (idx > -1) {
       $http.post(urlBase + '/tasks/' +taskId+'/ACTIVE').
    success(function(data) {
    alert("Task unmarked");
    $scope.tasks = data;
      });
       $scope.selection.splice(idx, 1);
     }

     // is newly selected
     else {
       $http.post(urlBase + '/tasks/' +taskId+'/COMPLETED').
    success(function(data) {
    alert("Task marked completed");
    $scope.tasks = data;
      });
       $scope.selection.push(taskId);
     }
   };

 // Archive Completed Tasks
   $scope.archiveTasks = function archiveTasks() {
    $http.post(urlBase + '/tasks/archive/' + $scope.selection).
    success(function(data) {
     $scope.tasks = data;
         alert("Successfully Archived");
      });
   };

});

//Angularjs Directive for confirm dialog box
taskManagerModule.directive('ngConfirmClick', [
 function(){
         return {
             link: function (scope, element, attr) {
                 var msg = attr.ngConfirmClick || "Are you sure?";
                 var clickAction = attr.confirmedClick;
                 element.bind('click',function (event) {
                     if ( window.confirm(msg) ) {
                         scope.$eval(clickAction);
                     }
                 });
             }
         };
 }]);

-- AngularJS gets activated with the ng-app directive placed in the html tag.

-- When the browser loads the div element with ng-controller directive 'taskManagerController', the controller module in the above javascript file executes. It makes http call to get all tasks initially and display in the jsp file.

--  When the user checks the check box placed near every task, the task is marked completed and when the user unchecks the check box, the task is again marked active.

-- On clicking 'Clear Completed Tasks' button, archiveTasks() method in the above javascript file is executed and all the tasks that are marked as completed are archived by changing the value of task_archived field in the database to 1. This method makes an http post request to the server to change the task_archived field value of all completed tasks. Note that we are just archiving the tasks but not deleting it, so it will always be there in the database but won't show up in the application.

-- A new task entry is added to the database by making an http post when the user clicks on 'Add task' button.

To understand how this application works, you can see a simple static demonstration using the demo link below. To completely understand how this works from the server side with a database, download the application and run it yourself using the instructions below.

DEMO DOWNLOAD

Instructions to run the download

1. Download the project using the download link above and unzip it.

2. Follow Step 1 of this article to create a database, table with dummy values. Simply execute the given query.

3. Make sure MySql Service is running.

4. Import the downloaded project in eclipse.

5. Right Click 'index.jsp' and run it in Tomcat Web Server v7.0

6. Note that you need data connection to get angularjs up and running in the project as we have referenced the latest version from angularjs cdn repository directly. You can also download angularjs library and reference it in index.jsp

You must be seeing the following page once you run it from Tomcat Web Server,

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