chore: updated examples

Author: Marvin Zhang

README.md

@@ -11,7 +11,21 @@ mvn clean install
 
 ## Usage
 
+Add the following dependency to your `pom.xml` file:
+
+```xml
+<dependency>
+    <groupId>io.crawlab</groupId>
+    <artifactId>sdk</artifactId>
+    <version>1.0.0</version>
+</dependency>
+```
+
+Then you can use the SDK in your Java code:
+
 ```java
+package com.example;
+
 import java.util.ArrayList;
 import java.util.Map;
 import java.util.HashMap;
@@ -50,11 +64,14 @@ public class Main {
         );
 
         // Using custom objects
-        public class Person {
+        class Person {
             private String name;
             private int age;
 
-            // Constructor, getters, setters...
+            public Person(String name, int age) {
+                this.name = name;
+                this.age = age;
+            }
         }
 
         Person person1 = new Person("John", 25);

src/main/java/io/crawlab/example/Main.java

@@ -0,0 +1,55 @@
+package io.crawlab.example;
+
+import java.util.ArrayList;
+import java.util.Map;
+import java.util.HashMap;
+import java.util.Arrays;
+
+import io.crawlab.sdk.CrawlabSDK;
+
+public class Main {
+    public static void main(String[] args) {
+        // Save a data item (will be serialized to JSON)
+        Map<String, Object> data = Map.of("name", "John", "age", 25);
+        CrawlabSDK.saveItem(data);
+
+        // Save multiple data items
+        Map<String, Object> data1 = Map.of("name", "John", "age", 25);
+        Map<String, Object> data2 = Map.of("name", "Jane", "age", 30);
+        CrawlabSDK.saveItem(data1, data2);
+
+        // Save dynamic-sized data items
+        ArrayList<Map<String, Object>> dataList = new ArrayList<>();
+        dataList.add(Map.of("name", "John", "age", 25));
+        dataList.add(Map.of("name", "Jane", "age", 30));
+        CrawlabSDK.saveItem(dataList);
+
+        // Passing Dynamic Arguments
+        Map<String, Object> dataMap = new HashMap<>();
+        dataMap.put("name", "John");
+        dataMap.put("age", 25);
+        dataMap.put("skills", Arrays.asList("Java", "Python"));
+        CrawlabSDK.saveItem(dataMap);
+
+        // Using varargs for multiple items
+        CrawlabSDK.saveItem(
+                Map.of("name", "John", "age", 25),
+                Map.of("name", "Jane", "age", 30)
+        );
+
+        // Using custom objects
+        class Person {
+            private String name;
+            private int age;
+
+            public Person(String name, int age) {
+                this.name = name;
+                this.age = age;
+            }
+        }
+
+        Person person1 = new Person("John", 25);
+        Person person2 = new Person("Jane", 30);
+        CrawlabSDK.saveItem(person1, person2);
+    }
+}