diff --git a/src/Contact.java b/src/Contact.java
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+++ b/src/Contact.java
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+/*
+ * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.micode.notes.data;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.provider.ContactsContract.CommonDataKinds.Phone;
+import android.provider.ContactsContract.Data;
+import android.telephony.PhoneNumberUtils;
+import android.util.Log;
+
+import java.util.HashMap;
+
+public class Contact {
+    // 静态缓存，用于存储已查询过的电话号码对应的联系人姓名
+    private static HashMap<String, String> sContactCache;
+    // 用于日志记录的标签
+    private static final String TAG = "Contact";
+
+    // 查询条件，用于根据电话号码查询联系人姓名
+    private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER
+    + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'"
+    + " AND " + Data.RAW_CONTACT_ID + " IN "
+            + "(SELECT raw_contact_id "
+            + " FROM phone_lookup"
+            + " WHERE min_match = '+')";
+
+    /**
+     * 获取电话号码对应的联系人姓名
+     * @param context 应用程序的上下文
+     * @param phoneNumber 要查询的电话号码
+     * @return 返回电话号码对应的联系人姓名，如果找不到则返回null
+     */
+    public static String getContact(Context context, String phoneNumber) {
+        // 初始化缓存
+        if(sContactCache == null) {
+            sContactCache = new HashMap<String, String>();
+        }
+
+        // 如果缓存中已经有该电话号码的联系人信息，直接返回
+        if(sContactCache.containsKey(phoneNumber)) {
+            return sContactCache.get(phoneNumber);
+        }
+
+        // 使用电话号码生成查询条件
+        String selection = CALLER_ID_SELECTION.replace("+",
+                PhoneNumberUtils.toCallerIDMinMatch(phoneNumber));
+
+        // 查询联系人信息
+        Cursor cursor = context.getContentResolver().query(
+                Data.CONTENT_URI,
+                new String [] { Phone.DISPLAY_NAME },  // 需要获取的字段，这里是联系人姓名
+                selection,  // 查询条件
+                new String[] { phoneNumber },  // 查询参数，填充到查询条件中
+                null);  // 排序方式，null表示不排序
+
+        // 检查查询结果并返回联系人姓名
+        if (cursor != null && cursor.moveToFirst()) {
+            try {
+                String name = cursor.getString(0);  // 获取查询到的联系人姓名
+                sContactCache.put(phoneNumber, name);  // 将结果缓存起来
+                return name;  // 返回联系人姓名
+            } catch (IndexOutOfBoundsException e) {
+                // 捕捉异常并记录错误日志
+                Log.e(TAG, " Cursor get string error " + e.toString());
+                return null;
+            } finally {
+                // 关闭游标，释放资源
+                cursor.close();
+            }
+        } else {
+            // 如果没有匹配的联系人，记录日志并返回null
+            Log.d(TAG, "No contact matched with number:" + phoneNumber);
+            return null;
+        }
+    }
+}