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华为Harmony鸿蒙开发笔记五：DataAbility操作数据库_鸿蒙开发如何连接数据库

作者：你好赵伟 | 2024-03-14 19:26:31

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鸿蒙开发如何连接数据库

学习鸿蒙应用开发，在DataAbility这里卡了好久，因为官方文档太简单了，漏掉了很多的东西，还好网上已经有大神已经做出来了，我查查资料，也做出自己的Demo来了。

首先，在模块的build.gradle文件中添加compileOptions{            annotationEnabled true    }

  1. apply plugin: 'com.huawei.ohos.hap'
  2. ohos {
  3.     compileSdkVersion 4
  4.     defaultConfig {
  5.         compatibleSdkVersion 3
  6.     }
  7.     compileOptions{            annotationEnabled true    }
  8. }
  9.  
  10. dependencies {
  11.     implementation fileTree(dir: 'libs', include: ['*.jar', '*.har'])
  12.     testCompile'junit:junit:4.12'
  13. }

不添加的话，数据库的相关类的的包无法识别。

同步以后就可以创建数据库的类BookStore了：

  1. package com.example.dataabilitydemo;
  2.  
  3. import ohos.data.orm.OrmDatabase;
  4. import ohos.data.orm.annotation.Database;
  5.  
  6. @Database(entities = {User.class}, version = 1)
  7. public abstract class BookStore extends OrmDatabase {
  8. }

然后再创建数据表User了：

  1. package com.example.dataabilitydemo;
  2.  
  3. import ohos.data.orm.OrmObject;
  4. import ohos.data.orm.annotation.Entity;
  5. import ohos.data.orm.annotation.Index;
  6. import ohos.data.orm.annotation.PrimaryKey;
  7.  
  8. @Entity(tableName = "user", ignoredColumns = {"ignoreColumn1", "ignoreColumn2"},
  9.         indices = {@Index(value = {"firstName", "lastName"}, name = "name_index", unique = true)})
  10. public class User extends OrmObject {
  11.     // 此处将userId设为了自增的主键。注意只有在数据类型为包装类型时，自增主键才能生效。
  12.     @PrimaryKey(autoGenerate = true)
  13.     private Integer userId;
  14.     private String firstName;
  15.     private String lastName;
  16.     private int age;
  17.     private double balance;
  18.     private int ignoreColumn1;
  19.     private int ignoreColumn2;
  20.     // 开发者自行添加字段的getter和setter 方法。
  21.  
  22.     public Integer getUserId() {
  23.         return userId;
  24.     }
  25.  
  26.     public void setUserId(Integer userId) {
  27.         this.userId = userId;
  28.     }
  29.  
  30.     public String getFirstName() {
  31.         return firstName;
  32.     }
  33.  
  34.     public void setFirstName(String firstName) {
  35.         this.firstName = firstName;
  36.     }
  37.  
  38.     public String getLastName() {
  39.         return lastName;
  40.     }
  41.  
  42.     public void setLastName(String lastName) {
  43.         this.lastName = lastName;
  44.     }
  45.  
  46.     public int getAge() {
  47.         return age;
  48.     }
  49.  
  50.     public void setAge(int age) {
  51.         this.age = age;
  52.     }
  53.  
  54.     public double getBalance() {
  55.         return balance;
  56.     }
  57.  
  58.     public void setBalance(double balance) {
  59.         this.balance = balance;
  60.     }
  61.  
  62.     public int getIgnoreColumn1() {
  63.         return ignoreColumn1;
  64.     }
  65.  
  66.     public void setIgnoreColumn1(int ignoreColumn1) {
  67.         this.ignoreColumn1 = ignoreColumn1;
  68.     }
  69.  
  70.     public int getIgnoreColumn2() {
  71.         return ignoreColumn2;
  72.     }
  73.  
  74.     public void setIgnoreColumn2(int ignoreColumn2) {
  75.         this.ignoreColumn2 = ignoreColumn2;
  76.     }
  77. }

下面就可以创建DataAbility了

有人说创建的时候要勾选visible,可是我这根本就没有这个选项，不过没关系，名字就叫UserDataAbility

创建后，配置config，

  1.     "abilities": [
  2.       ...........
  3.       {
  4.         "visible": true,
  5.         "permissions": [
  6.           "com.example.dataabilitydemo.UserDataAbility.DATA"
  7.         ],
  8.         "name": "com.example.dataabilitydemo.UserDataAbility",
  9.         "icon": "$media:icon",
  10.         "description": "$string:userdataability_description",
  11.         "type": "data",
  12.         "uri": "dataability://com.example.dataabilitydemo.UserDataAbility"
  13.       }
  14.     ]

其中"visible": true就是弥补创建页面没有visible勾选项的，permissions，name，uri这些项的值不一定非得是包名+类名，但保险起见，大家还是按规矩来。

然后就可以编辑UserDataAbility类了，首先，定义全局变量，并在onStart方法实现DatabaseHelper对象，用来操作数据库，并插入一条数据。

  1. rivate String uriString="dataability://com.example.dataabilitydemo.UserDataAbility";//这里要跟config.json中的URI保持一致
  2.     private static final String DATABASE_NAME ="BookStore.db";
  3.     private static final String DATABASE_NAME_ALIAS = "BookStore";
  4.     private static OrmContext ormContext = null;
  5.     private static final HiLogLabel LABEL_LOG = new HiLogLabel(3, 0xD001100, "My_log");
  6.  
  7.     @Override
  8.     public void onStart(Intent intent) {
  9.         super.onStart(intent);
  10.         DatabaseHelper helper = new DatabaseHelper(this); 
  11.         ormContext = helper.getOrmContext(DATABASE_NAME_ALIAS, DATABASE_NAME, BookStore.class);
  12.         User user = new User();
  13.         user.setFirstName("Zhang");
  14.         user.setLastName("San");
  15.         user.setAge(29);
  16.         user.setBalance(100.51);
  17.         boolean isSuccessed = ormContext.insert(user);
  18.         isSuccessed = ormContext.flush();
  19.         HiLog.info(LABEL_LOG, "ProviderAbility onStart");
  20.     }

然后重写query方法，用来查询：

  1.     @Override
  2.     public ResultSet query(Uri uri, String[] columns, DataAbilityPredicates predicates) {
  3.         HiLog.info(LABEL_LOG, "ProviderAbility query");
  4.         if(ormContext == null){
  5.             HiLog.error(LABEL_LOG,"failed to query, ormContext is null");
  6.             return null;
  7.         }
  8.         //查询数据库
  9.         OrmPredicates ormPredicates = DataAbilityUtils.createOrmPredicates(predicates, User.class);
  10.         ResultSet resultSet = ormContext.query(ormPredicates,columns);
  11.         if (resultSet == null){
  12.             HiLog.info(LABEL_LOG,"resultSet is null");
  13.         }
  14.         return resultSet;
  15.     }

最后，在MainAbilitySlice来调用，其他的Ability要是访问DataAbility，就需要在config.json中授予访问权限，如下

  1.         "orientation": "unspecified",
  2.         "name": "com.example.dataabilitydemo.MainAbility",
  3.         "icon": "$media:icon",
  4.         "description": "$string:mainability_description",
  5.         "label": "DataAbilityDemo",
  6.         "type": "page",
  7.         "launchType": "standard",
  8.          //下面的name要跟DataAbility里的permissions保持一致呀
  9.         "reqPermissions": [ { "name": "com.example.dataabilitydemo.UserDataAbility.DATA" }]

配置完就可以在Slice里写代码啦：

  1. public class MainAbilitySlice extends AbilitySlice {
  2.     //下面的uriString要与config.json中DataAbility的uri保持一致，但是坑爹的事他有三个斜杠
  3.     private String uriString = "dataability:///com.example.dataabilitydemo.UserDataAbility";
  4.     private static final HiLogLabel LABEL_LOG = new HiLogLabel(3, 0xD001100, "My_log");
  5.     private DataAbilityHelper helper;
  6.     @Override
  7.     public void onStart(Intent intent) {
  8.         super.onStart(intent);
  9.         super.setUIContent(ResourceTable.Layout_ability_main);
  10.         helper = DataAbilityHelper.creator(this);
  11.         Button btnDataSelect = (Button) findComponentById(ResourceTable.Id_btn_data_select);
  12.         if (btnDataSelect != null) {
  13.             // 为按钮设置点击回调
  14.             btnDataSelect.setClickedListener(new Component.ClickedListener() {
  15.                 @Override
  16.                 public void onClick(Component component) {
  17.                     try {
  18.                         queryDataAbility();
  19.                     } catch (DataAbilityRemoteException e) {
  20.                         e.printStackTrace();
  21.                     }
  22.                 }
  23.             });
  24.         }
  25.     }
  26.  
  27.     public void queryDataAbility() throws DataAbilityRemoteException {
  28.         // 构造查询条件
  29.         DataAbilityPredicates predicates = new DataAbilityPredicates();
  30.         predicates.equalTo("lastName", "San");
  31.         // 进行查询
  32.         String[] columns = new String[]{"firstName"};
  33.         Uri uri = Uri.parse(uriString);
  34.         ResultSet resultSet = helper.query(uri, columns, predicates);
  35.         // 处理结果
  36.         HiLog.info(LABEL_LOG, "queryDataAbilitystart");
  37.         resultSet.goToFirstRow();
  38.         do {
  39.             // 在此处理ResultSet中的记录;
  40.             HiLog.info(LABEL_LOG, "firstName=" + resultSet.getString(0));
  41.         } while (resultSet.goToNextRow());
  42.     }
  43. }

就是单击按钮，查询一个lastName叫san的人他的firstName：

  1. 12-31 21:37:18.617 22937-5343/? I 01100/My_log: ProviderAbility onStart
  2. 12-31 21:37:26.628 22937-22937/com.example.dataabilitydemo I 01100/My_log: ProviderAbility query
  3. 12-31 21:37:26.632 22937-22937/com.example.dataabilitydemo I 01100/My_log: queryDataAbilitystart
  4. 12-31 21:37:26.633 22937-22937/com.example.dataabilitydemo I 01100/My_log: firstName=Zhang

简单的查询功能就完成啦。

既然查询能走通，那么继续试试其他的，先插入一条数据吧，首先重新DataAbility的insert方法：

  1.     @Override
  2.     public int insert(Uri uri, ValuesBucket value) {
  3. // 参数校验
  4.         HiLog.info(LABEL_LOG, "UserDataAbility insert");
  5.         if (ormContext == null) {
  6.             HiLog.error(LABEL_LOG, "failed to insert, ormContext is null");
  7.             return -1;
  8.         }
  9.  
  10.         // 构造插入数据
  11.         User user = new User();
  12.         user.setUserId(value.getInteger("userId"));
  13.         user.setFirstName(value.getString("firstName"));
  14.         user.setLastName(value.getString("lastName"));
  15.         user.setAge(value.getInteger("age"));
  16.         user.setBalance(value.getDouble("balance"));
  17.  
  18.         // 插入数据库
  19.         boolean isSuccessed = true;
  20.         isSuccessed = ormContext.insert(user);
  21.         if (!isSuccessed) {
  22.             HiLog.error(LABEL_LOG, "failed to insert");
  23.             return -1;
  24.         }
  25.         isSuccessed = ormContext.flush();
  26.         if (!isSuccessed) {
  27.             HiLog.error(LABEL_LOG, "failed to insert flush");
  28.             return -1;
  29.         }
  30.         DataAbilityHelper.creator(this, uri).notifyChange(uri);
  31.         int id = Math.toIntExact(user.getRowId());
  32.         HiLog.info(LABEL_LOG, "UserDataAbility insert id="+id);
  33.         return id;
  34.     }

在Slice中先调用插入，然后再查询我们插入的数据：

  1. public void queryDataAbility() throws DataAbilityRemoteException {
  2.         // 构造查询条件
  3.         DataAbilityPredicates predicates = new DataAbilityPredicates();
  4.         predicates.equalTo("lastName", "史蒂夫");
  5.         // 进行查询
  6.         String[] columns = new String[]{"firstName"};
  7.         Uri uri = Uri.parse(uriString);
  8.         ResultSet resultSet = helper.query(uri, columns, predicates);
  9.         // 处理结果
  10.         HiLog.info(LABEL_LOG, "queryDataAbilitystart");
  11.         resultSet.goToFirstRow();
  12.         do {
  13.             // 在此处理ResultSet中的记录;
  14.             HiLog.info(LABEL_LOG, "firstName=" + resultSet.getString(0));
  15.         } while (resultSet.goToNextRow());
  16.     }
  17.     public void insertDataAbility() throws DataAbilityRemoteException {
  18.         // 构造插入数据
  19.         HiLog.info(LABEL_LOG, "MainAbilitySlice insertDataAbility");
  20.         DataAbilityHelper helper = DataAbilityHelper.creator(this);
  21.         Uri uri = Uri.parse(uriString);
  22.         ValuesBucket valuesBucket = new ValuesBucket();
  23.         valuesBucket.putString("firstName", "孬蛋");
  24.         valuesBucket.putString("lastName", "史蒂夫");
  25.         valuesBucket.putInteger("age", 12);
  26.         valuesBucket.putDouble("balance", 200.0);
  27.         helper.insert(uri, valuesBucket);
  28.     }

日志输出：

  1. 01-01 09:18:21.256 20487-20487/com.example.dataabilitydemo I 01100/My_log: MainAbilitySlice insertDataAbility
  2. 01-01 09:18:21.262 20487-20487/com.example.dataabilitydemo I 01100/My_log: UserDataAbility insert
  3. 01-01 09:18:21.270 20487-20487/com.example.dataabilitydemo I 01100/My_log: UserDataAbility insert id=2
  4. 01-01 09:18:30.485 20487-20487/com.example.dataabilitydemo I 01100/My_log: ProviderAbility query
  5. 01-01 09:18:30.505 20487-20487/com.example.dataabilitydemo I 01100/My_log: queryDataAbilitystart
  6. 01-01 09:18:30.506 20487-20487/com.example.dataabilitydemo I 01100/My_log: firstName=孬蛋

再试试修改我们插入的数据，重写DataAbility的update方法：

  1.     @Override
  2.     public int update(Uri uri, ValuesBucket value, DataAbilityPredicates predicates) {
  3.         if (ormContext == null) {
  4.             HiLog.error(LABEL_LOG, "failed to update, ormContext is null");
  5.             return -1;
  6.         }
  7.  
  8.         OrmPredicates ormPredicates = DataAbilityUtils.createOrmPredicates(predicates,User.class);
  9.         int index = ormContext.update(ormPredicates, value);
  10.         HiLog.info(LABEL_LOG, "UserDataAbility update value:" + index);
  11.         DataAbilityHelper.creator(this, uri).notifyChange(uri);
  12.         return index;
  13.     }

在Slice中，更新刚插入的数据，修改她的名字，然后再查询：

  1. public void updateDataAbility() throws DataAbilityRemoteException {
  2.         // 构造插入数据
  3.         DataAbilityHelper helper = DataAbilityHelper.creator(this);
  4.  
  5. // 构造更新条件
  6.         DataAbilityPredicates predicates = new DataAbilityPredicates();
  7.         predicates.equalTo("lastName", "史蒂夫");
  8.  
  9. // 构造更新数据
  10.         ValuesBucket valuesBucket = new ValuesBucket();
  11.         valuesBucket.putString("firstName", "小精豆");
  12.         valuesBucket.putInteger("age", 12);
  13.         Uri uri = Uri.parse(uriString);
  14.         try {
  15.             helper.update(uri, valuesBucket, predicates);
  16.         } catch (DataAbilityRemoteException e) {
  17.             e.printStackTrace();
  18.         }
  19.     }

结果（一定要先插入，再查询）：

  1. 01-01 10:21:47.149 26565-26565/com.example.dataabilitydemo I 01100/My_log: ProviderAbility query
  2. 01-01 10:21:47.156 26565-26565/com.example.dataabilitydemo I 01100/My_log: queryDataAbilitystart
  3. 01-01 10:21:47.157 26565-26565/com.example.dataabilitydemo I 01100/My_log: firstName=孬蛋
  4. 01-01 10:21:51.961 26565-26565/com.example.dataabilitydemo I 01100/My_log: MainAbilitySlice updateDataAbility
  5. 01-01 10:21:51.966 26565-26565/com.example.dataabilitydemo I 01100/My_log: UserDataAbility update value:1
  6. 01-01 10:21:54.741 26565-26565/com.example.dataabilitydemo I 01100/My_log: ProviderAbility query
  7. 01-01 10:21:54.743 26565-26565/com.example.dataabilitydemo I 01100/My_log: queryDataAbilitystart
  8. 01-01 10:21:54.744 26565-26565/com.example.dataabilitydemo I 01100/My_log: firstName=小精豆

最后，删除这条数据，DataAbility的delete()方法：

  1.     @Override
  2.     public int delete(Uri uri, DataAbilityPredicates predicates) {
  3.         if (ormContext == null) {
  4.             HiLog.error(LABEL_LOG, "failed to delete, ormContext is null");
  5.             return -1;
  6.         }
  7.  
  8.         OrmPredicates ormPredicates = DataAbilityUtils.createOrmPredicates(predicates,User.class);
  9.         int value = ormContext.delete(ormPredicates);
  10.         DataAbilityHelper.creator(this, uri).notifyChange(uri);
  11.         return value;
  12.     }

访问：

  1.     public void deleteDataAbility() throws DataAbilityRemoteException {
  2.         DataAbilityHelper helper = DataAbilityHelper.creator(this);
  3.         Uri uri = Uri.parse(uriString);
  4. // 构造删除条件
  5.         DataAbilityPredicates predicates = new DataAbilityPredicates();
  6.         predicates.equalTo("lastName", "史蒂夫");
  7.         helper.delete(uri,predicates);
  8.     }

增删改查就都写好了

Demo：https://download.csdn.net/download/y280903468/13999695

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