# Network Connection Management


> **NOTE**<br/>
>
> The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version.

## Modules to Import

```javascript
import connection from '@ohos.net.connection'
```

## connection.getDefaultNet

getDefaultNet(callback: AsyncCallback\<NetHandle>): void

Obtains the default active data network. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                                   | Mandatory| Description      |
| -------- | --------------------------------------- | ---- | ---------- |
| callback | AsyncCallback\<[NetHandle](#nethandle)> | Yes  | Callback used to return the result.|

**Example**

```javascript
connection.getDefaultNet(function (error, netHandle) {
    console.log(JSON.stringify(error))
    console.log(JSON.stringify(netHandle))
})
```

## connection.getDefaultNet

getDefaultNet(): Promise\<NetHandle>

Obtains the default active data network. This API uses a promise to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO

**System capability**: SystemCapability.Communication.NetManager.Core

**Return value**

| Type                             | Description                                 |
| --------------------------------- | ------------------------------------- |
| Promise\<[NetHandle](#nethandle)> | Promise used to return the result.|

**Example**

```javascript
connection.getDefaultNet().then(function (netHandle) {
    console.log(JSON.stringify(netHandle))
})
```

## connection.hasDefaultNet

hasDefaultNet(callback: AsyncCallback\<boolean>): void

Checks whether the default data network is activated. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                   | Mandatory| Description                                  |
| -------- | ----------------------- | ---- | -------------------------------------- |
| callback | AsyncCallback\<boolean> | Yes  | Callback used to return the result. The value **true** indicates that the default data network is activated.|

**Example**

```javascript
connection.hasDefaultNet(function (error, has) {
    console.log(JSON.stringify(error))
    console.log(has)
})
```

## connection.hasDefaultNet

hasDefaultNet(): Promise\<boolean>

Checks whether the default data network is activated. This API uses a promise to return the result.

**System capability**: SystemCapability.Communication.NetManager.Core

**Return value**

| Type             | Description                                           |
| ----------------- | ----------------------------------------------- |
| Promise\<boolean> | Promise used to return the result. The value **true** indicates that the default data network is activated.|

**Example**

```javascript
connection.hasDefaultNet().then(function (has) {
    console.log(has)
})
```

## connection.getAllNets

getAllNets(callback: AsyncCallback&lt;Array&lt;NetHandle&gt;&gt;): void

Obtains the list of all active data networks. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;Array&lt;[NetHandle](#nethandle)&gt;&gt; | Yes| Callback used to return the result.|

**Example**

```
connection.getAllNets(function (error, nets) {
    console.log(JSON.stringify(error))
    console.log(JSON.stringify(nets))
});
```


## connection.getAllNets

getAllNets(): Promise&lt;Array&lt;NetHandle&gt;&gt;

Obtains the list of all active data networks. This API uses a promise to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO

**System capability**: SystemCapability.Communication.NetManager.Core

**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;Array&lt;[NetHandle](#nethandle)&gt;&gt; | Promise used to return the result.|

**Example**

```
connection.getAllNets().then(function (nets) {
    console.log(JSON.stringify(nets))
});
```

## connection.getConnectionProperties

getConnectionProperties(netHandle: NetHandle, callback: AsyncCallback\<ConnectionProperties>): void

Obtains connection properties of the network corresponding to the **netHandle**. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name   | Type                                                        | Mandatory| Description            |
| --------- | ------------------------------------------------------------ | ---- | ---------------- |
| netHandle | [NetHandle](#nethandle)                                      | Yes  | Network handle.|
| callback  | AsyncCallback\<[ConnectionProperties](#connectionproperties)> | Yes  | Callback used to return the result.      |

**Example**

```javascript
connection.getDefaultNet().then(function (netHandle) {
    connection.getConnectionProperties(netHandle, function (error, info) {
        console.log(JSON.stringify(error))
        console.log(JSON.stringify(info))
    })
})
```

## connection.getConnectionProperties

getConnectionProperties(netHandle: NetHandle): Promise\<ConnectionProperties>

Obtains connection properties of the network corresponding to the **netHandle**. This API uses a promise to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name   | Type                   | Mandatory| Description            |
| --------- | ----------------------- | ---- | ---------------- |
| netHandle | [NetHandle](#nethandle) | Yes  | Network handle.|

**Return value**

| Type                                                   | Description                             |
| ------------------------------------------------------- | --------------------------------- |
| Promise\<[ConnectionProperties](#connectionproperties)> | Promise used to return the result.|

**Example**

```javascript
connection.getDefaultNet().then(function (netHandle) {
    connection.getConnectionProperties(netHandle).then(function (info) {
        console.log(JSON.stringify(info))
    })
})
```

## connection.getNetCapabilities

getNetCapabilities(netHandle: NetHandle, callback: AsyncCallback\<NetCapabilities>): void

Obtains capability information of the network corresponding to the **netHandle**. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name   | Type                                               | Mandatory| Description            |
| --------- | --------------------------------------------------- | ---- | ---------------- |
| netHandle | [NetHandle](#nethandle)                             | Yes  | Network handle.|
| callback  | AsyncCallback\<[NetCapabilities](#netcapabilities)> | Yes  | Callback used to return the result.      |

**Example**

```javascript
connection.getDefaultNet().then(function (netHandle) {
    connection.getNetCapabilities(netHandle, function (error, info) {
        console.log(JSON.stringify(error))
        console.log(JSON.stringify(info))
    })
})
```

## connection.getNetCapabilities

getNetCapabilities(netHandle: NetHandle): Promise\<NetCapabilities>

Obtains capability information of the network corresponding to the **netHandle**. This API uses a promise to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name   | Type                   | Mandatory| Description            |
| --------- | ----------------------- | ---- | ---------------- |
| netHandle | [NetHandle](#nethandle) | Yes  | Network handle.|

**Return value**

| Type                                         | Description                             |
| --------------------------------------------- | --------------------------------- |
| Promise\<[NetCapabilities](#netcapabilities)> | Promise used to return the result.|

**Example**

```javascript
connection.getDefaultNet().then(function (netHandle) {
    connection.getNetCapabilities(netHandle).then(function (info) {
        console.log(JSON.stringify(info))
    })
})
```

## connection.reportNetConnected

reportNetConnected(netHandle: NetHandle, callback: AsyncCallback&lt;void&gt;): void

Reports connection of the data network. This API uses an asynchronous callback to return the result.

**Required permissions** : ohos.permission.GET_NETWORK_INFO and ohos.permission.INTERNET

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| netHandle | [NetHandle](#nethandle) | Yes| Handle of the data network. For details, see [NetHandle](#nethandle).|
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the result.|

**Example**

```
connection.getDefaultNet().then(function (netHandle) {
    connection.reportNetConnected(netHandle, function (error) {
        console.log(JSON.stringify(error))
    });
});
```


## connection.reportNetConnected

reportNetConnected(netHandle: NetHandle): Promise&lt;void&gt;

Reports connection of the data network. This API uses a promise to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO and ohos.permission.INTERNET

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| netHandle | [NetHandle](#nethandle) | Yes| Handle of the data network. For details, see [NetHandle](#nethandle).|

**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise used to return the result.|

**Example**

```
connection.getDefaultNet().then(function (netHandle) {
    connection.reportNetConnected(netHandle).then(function () {
        console.log(`report success`)
    });
});
```


## connection.reportNetDisconnected

reportNetDisconnected(netHandle: NetHandle, callback: AsyncCallback&lt;void&gt;): void

Reports disconnection of the data network. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO and ohos.permission.INTERNET

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| netHandle | [NetHandle](#nethandle) | Yes| Handle of the data network. For details, see [NetHandle](#nethandle).|
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the result.|

**Example**

```
connection.getDefaultNet().then(function (netHandle) {
    connection.reportNetDisconnected(netHandle, function (error) {
        console.log(JSON.stringify(error))
    });
});
```


## connection.reportNetDisconnected

reportNetDisconnected(netHandle: NetHandle): Promise&lt;void&gt;

Reports disconnection of the data network. This API uses a promise to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO and ohos.permission.INTERNET

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| netHandle | [NetHandle](#nethandle) | Yes| Handle of the data network. For details, see [NetHandle](#nethandle).|

**Return value**
| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise used to return the result.|

**Example**

```
connection.getDefaultNet().then(function (netHandle) {
    connection.reportNetDisconnected(netHandle).then(function () {
        console.log(`report success`)
    });
});
```

## connection.getAddressesByName

getAddressesByName(host: string, callback: AsyncCallback\<Array\<NetAddress>>): void

Resolves the host name by using the default network to obtain all IP addresses. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                                             | Mandatory| Description              |
| -------- | ------------------------------------------------- | ---- | ------------------ |
| host     | string                                            | Yes  | Host name to resolve.|
| callback | AsyncCallback\<Array\<[NetAddress](#netaddress)>> | Yes  | Callback used to return the result.        |

**Example**

```
let host = "xxxx";
connection.getAddressesByName(host, function (error, addresses) {
    console.log(JSON.stringify(error))
    console.log(JSON.stringify(addresses))
})
```

## connection.getAddressesByName

getAddressesByName(host: string): Promise\<Array\<NetAddress>>

Resolves the host name by using the default network to obtain all IP addresses. This API uses a promise to return the result.

**Required permissions**: ohos.permission.GET_NETWORK_INFO

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name| Type  | Mandatory| Description              |
| ------ | ------ | ---- | ------------------ |
| host   | string | Yes  | Host name to resolve.|

**Return value**

| Type                                       | Description                         |
| ------------------------------------------- | ----------------------------- |
| Promise\<Array\<[NetAddress](#netaddress)>> | Promise used to return the IP addresses obtained.|

**Example**

```
let host = "xxxx";
connection.getAddressesByName(host).then(function (addresses) {
    console.log(JSON.stringify(addresses))
})
```

## connection.createNetConnection

createNetConnection(netSpecifier?: NetSpecifier, timeout?: number): NetConnection

Obtains the handle of the network specified by **netSpecifier**.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name      | Type                         | Mandatory| Description                                                        |
| ------------ | ----------------------------- | ---- | ------------------------------------------------------------ |
| netSpecifier | [NetSpecifier](#netspecifier) | No  | Network specifier. If this parameter is not set, the default network is used.                  |
| timeout      | number                        | No  | Timeout interval for obtaining the network specified by **netSpecifier**. This parameter is valid only when **netSpecifier** is set.|

**Return value**

| Type                           | Description                |
| ------------------------------- | -------------------- |
| [NetConnection](#netconnection) | Handle of the network specified by **netSpecifier**.|

**Example**

```javascript
// Default network
let netConnection = connection.createNetConnection()

// Cellular network
let netConnectionCellular = connection.createNetConnection({
    netCapabilities: {
        bearerTypes: [NetBearType.BEARER_CELLULAR]
    }
})
```

## NetConnection

Represents the network connection handle.

### on('netAvailable')

on(type: 'netAvailable', callback: Callback\<NetHandle>): void

Registers a listener for **netAvailable** events.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                              | Mandatory| Description                                                        |
| -------- | ---------------------------------- | ---- | ------------------------------------------------------------ |
| type     | string                             | Yes  | Event type. The value is fixed to **netAvailable**.<br>**netAvailable**: event indicating that the data network is available.|
| callback | Callback\<[NetHandle](#nethandle)> | Yes  | Callback used to return the result.                                                  |

**Example**

```javascript
netConnection.on('netAvailable', function (data) {
    console.log(JSON.stringify(data))
})
```

### on('netCapabilitiesChange')

on(type: 'netCapabilitiesChange', callback: Callback<{ netHandle: NetHandle, netCap: NetCapabilities }>): void

Registers a listener for **netCapabilitiesChange** events.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                                                        | Mandatory| Description                                                        |
| -------- | ------------------------------------------------------------ | ---- | ------------------------------------------------------------ |
| type     | string                                                       | Yes  | Event type. The value is fixed to **netCapabilitiesChange**.<br>**netCapabilitiesChange**: event indicating that the network capabilities have changed.|
| callback | Callback<{ netHandle: [NetHandle](#nethandle), netCap: [NetCapabilities](#netcapabilities) }> | Yes  | Callback used to return the result.                                                  |

**Example**

```javascript
netConnection.on('netCapabilitiesChange', function (data) {
    console.log(JSON.stringify(data))
})
```

### on('netConnectionPropertiesChange')

on(type: 'netConnectionPropertiesChange', callback: Callback<{ netHandle: NetHandle, connectionProperties: ConnectionProperties }>): void

Registers a listener for **netConnectionPropertiesChange** events.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                                                        | Mandatory| Description                                                        |
| -------- | ------------------------------------------------------------ | ---- | ------------------------------------------------------------ |
| type     | string                                                       | Yes  | Event type. The value is fixed to **netConnectionPropertiesChange**.<br>**netConnectionPropertiesChange**: event indicating that network connection properties have changed.|
| callback | Callback<{ netHandle: [NetHandle](#nethandle), connectionProperties: [ConnectionProperties](#connectionproperties) }> | Yes  | Callback used to return the result.                                                  |

**Example**

```javascript
netConnection.on('netConnectionPropertiesChange', function (data) {
    console.log(JSON.stringify(data))
})
```

### on('netBlockStatusChange')

on(type: 'netBlockStatusChange', callback: Callback&lt;{ netHandle: NetHandle, blocked: boolean }&gt;): void

Registers a listener for **netBlockStatusChange** events.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                                                        | Mandatory| Description                                                        |
| -------- | ------------------------------------------------------------ | ---- | ------------------------------------------------------------ |
| type     | string                                                       | Yes  | Event type. The value is fixed to **netBlockStatusChange**.<br>**netBlockStatusChange**: event indicating a change in the network blocking status.|
| callback | Callback&lt;{&nbsp;netHandle:&nbsp;[NetHandle](#nethandle),&nbsp;blocked:&nbsp;boolean&nbsp;}&gt; | Yes  | Callback used to return the result.                                                  |

**Example**

```javascript
netConnection.on('netBlockStatusChange', function (data) {
    console.log(JSON.stringify(data))
})
```

### on('netLost')

on(type: 'netLost', callback: Callback\<NetHandle>): void

Registers a listener for **netLost** events.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                              | Mandatory| Description                                                        |
| -------- | ---------------------------------- | ---- | ------------------------------------------------------------ |
| type     | string                             | Yes  | Event type. The value is fixed to **netLost**.<br>netLost: event indicating that the network is interrupted or normally disconnected.|
| callback | Callback\<[NetHandle](#nethandle)> | Yes  | Callback used to return the result.                                                  |

**Example**

```javascript
let netConnection1 = connection.createNetConnection()
netConnection1.on('netLost', function (data) {
    console.log(JSON.stringify(data))
})
```

### on('netUnavailable')

on(type: 'netUnavailable', callback: Callback\<void>): void

Registers a listener for **netUnavailable** events.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type           | Mandatory| Description                                                        |
| -------- | --------------- | ---- | ------------------------------------------------------------ |
| type     | string          | Yes  | Event type. The value is fixed to **netUnavailable**.<br>**netUnavailable**: event indicating that the network is unavailable.|
| callback | Callback\<void> | Yes  | Callback used to return the result.                                                  |

**Example**

```javascript
netConnection.on('netUnavailable', function (data) {
    console.log(JSON.stringify(data))
})
```

### register

register(callback: AsyncCallback\<void>): void

Registers a listener for network status changes.

**Required permissions**: ohos.permission.GET_NETWORK_INFO

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                | Mandatory| Description      |
| -------- | -------------------- | ---- | ---------- |
| callback | AsyncCallback\<void> | Yes  | Callback used to return the result.|

**Example**

```javascript
netConnection.register(function (error) {
    console.log(JSON.stringify(error))
})
```

### unregister

unregister(callback: AsyncCallback\<void>): void

Unregisters the listener for network status changes.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                | Mandatory| Description      |
| -------- | -------------------- | ---- | ---------- |
| callback | AsyncCallback\<void> | Yes  | Callback used to return the result.|

**Example**

```javascript
netConnection.unregister(function (error) {
    console.log(JSON.stringify(error))
})
```

## NetHandle

Defines the handle of the data network.

Before invoking **NetHandle** APIs, call **getNetHandle** to obtain a **NetHandle** object.

**System capability**: SystemCapability.Communication.NetManager.Core

### Attributes

| Name| Type  | Description                     |
| ------ | ------ | ------------------------- |
| netId  | number | Network ID. The value must be greater than or equal to **100**.|

### bindSocket

bindSocket(socketParam: TCPSocket | UDPSocket, callback: AsyncCallback&lt;void&gt;): void

Binds a **TCPSocket** or **UDPSocket** object to the data network. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**
| Name     | Type                     | Mandatory| Description            |
| ----------- | ------------------------- | ---- | ---------------- |
| socketParam | TCPSocket \| UDPSocket    | Yes  | **TCPSocket** or **UDPSocket** object.|
| callback    | AsyncCallback&lt;void&gt; | Yes  | Callback used to return the result.      |

**Example**

```
// Bind the TCPSocket object.
connection.getDefaultNet().then(function (netHandle) {
    let tcpSocket = socket.constructTCPSocketInstance()
    netHandle.bindSocket(tcpSocket, (function (error) {
        console.log(JSON.stringify(error))
    }))
})
// Bind the UDPSocket object.
connection.getDefaultNet().then(function (netHandle) {
    let udpSocket = socket.constructUDPSocketInstance()
    netHandle.bindSocket(udpSocket, (function (error) {
        console.log(JSON.stringify(error))
    }))
})
```


### bindSocket

bindSocket(socketParam: TCPSocket | UDPSocket): Promise&lt;void&gt;

Binds a **TCPSocket** or **UDPSocket** object to the data network. This API uses a promise to return the result.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**
| Name     | Type                                                        | Mandatory| Description                                                        |
| ----------- | ------------------------------------------------------------ | ---- | ------------------------------------------------------------ |
| socketParam | TCPSocket \| UDPSocket    | Yes  | **TCPSocket** or **UDPSocket** object.|

**Return value**
| Type               | Description                       |
| ------------------- | --------------------------- |
| Promise&lt;void&gt; | Promise used to return the result.|

**Example**

```
// Bind the TCPSocket object.
connection.getDefaultNet().then(function (netHandle) {
    let tcpSocket = socket.constructTCPSocketInstance()
    netHandle.bindSocket(tcpSocket).then(function () {
        console.log("bind socket success")
    })
})
// Bind the UDPSocket object.
connection.getDefaultNet().then(function (netHandle) {
    let udpSocket = socket.constructUDPSocketInstance()
    netHandle.bindSocket(udpSocket).then(function () {
        console.log("bind socket success")
    })
})
```

### getAddressesByName

getAddressesByName(host: string, callback: AsyncCallback\<Array\<NetAddress>>): void

Resolves the host name by using the corresponding network to obtain all IP addresses. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                                             | Mandatory| Description              |
| -------- | ------------------------------------------------- | ---- | ------------------ |
| host     | string                                            | Yes  | Host name to resolve.|
| callback | AsyncCallback\<Array\<[NetAddress](#netaddress)>> | Yes  | Callback used to return the result.          |

**Example**

```javascript
connection.getDefaultNet().then(function (netHandle) {
    let host = "xxxx";
    netHandle.getAddressesByName(host, function (error, addresses) {
        console.log(JSON.stringify(error))
        console.log(JSON.stringify(addresses))
    })
})
```

### getAddressesByName

getAddressesByName(host: string): Promise\<Array\<NetAddress>>

Resolves the host name by using the corresponding network to obtain all IP addresses. This API uses a promise to return the result.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name| Type  | Mandatory| Description              |
| ------ | ------ | ---- | ------------------ |
| host   | string | Yes  | Host name to resolve.|

**Return value**

| Type                                       | Description                         |
| ------------------------------------------- | ----------------------------- |
| Promise\<Array\<[NetAddress](#netaddress)>> | Promise used to return the result.|

**Example**

```javascript
connection.getDefaultNet().then(function (netHandle) {
    let host = "xxxx";
    netHandle.getAddressesByName(host).then(function (addresses) {
        console.log(JSON.stringify(addresses))
    })
})
```

### getAddressByName

getAddressByName(host: string, callback: AsyncCallback\<NetAddress>): void

Resolves the host name by using the corresponding network to obtain the first IP address. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name  | Type                                     | Mandatory| Description              |
| -------- | ----------------------------------------- | ---- | ------------------ |
| host     | string                                    | Yes  | Host name to resolve.|
| callback | AsyncCallback\<[NetAddress](#netaddress)> | Yes  | Callback used to return the result.        |

**Example**

```javascript
connection.getDefaultNet().then(function (netHandle) {
    let host = "xxxx";
    netHandle.getAddressByName(host, function (error, address) {
        console.log(JSON.stringify(error))
        console.log(JSON.stringify(address))
    })
})
```

### getAddressByName

getAddressByName(host: string): Promise\<NetAddress>

Resolves the host name by using the corresponding network to obtain the first IP address. This API uses a promise to return the result.

**System capability**: SystemCapability.Communication.NetManager.Core

**Parameters**

| Name| Type  | Mandatory| Description              |
| ------ | ------ | ---- | ------------------ |
| host   | string | Yes  | Host name to resolve.|

**Return value**

| Type                               | Description                           |
| ----------------------------------- | ------------------------------- |
| Promise\<[NetAddress](#netaddress)> | Promise used to return the result.|

**Example**

```javascript
connection.getDefaultNet().then(function (netHandle) {
    let host = "xxxx";
    netHandle.getAddressByName(host).then(function (address) {
        console.log(JSON.stringify(address))
    })
})
```

## NetSpecifier

Provides an instance that bears data network capabilities.

**System capability**: SystemCapability.Communication.NetManager.Core

| Name                 | Type                               | Description                                                        |
| ----------------------- | ----------------------------------- | ------------------------------------------------------------ |
| netCapabilities         | [NetCapabilities](#netcapabilities) | Network transmission capabilities and bearer types of the data network.                          |
| bearerPrivateIdentifier | string                              | Network identifier. The identifier of a Wi-Fi network is **wifi**, and that of a cellular network is **slot0** (corresponding to SIM card 1).|

## NetCapabilities

Defines the network capability set.

**System capability**: SystemCapability.Communication.NetManager.Core

| Name               | Type                              | Description                    |
| --------------------- | ---------------------------------- | ------------------------ |
| linkUpBandwidthKbps   | number                             | Uplink (from the device to the network) bandwidth.|
| linkDownBandwidthKbps | number                             | Downlink (from the network to the device) bandwidth.|
| networkCap            | Array<[NetCap](#netcap)>           | Network capability.          |
| bearerTypes           | Array<[NetBearType](#netbearType)> | Network type.              |

## NetCap

Defines the network capability.

**System capability**: SystemCapability.Communication.NetManager.Core

| Name                 | Value α  | Description                  |
| ------------------------ | ---- | ---------------------- |
| NET_CAPABILITY_MMS | 0 | The network can connect to the carrier's Multimedia Messaging Service Center (MMSC) to send and receive multimedia messages.|
| NET_CAPABILITY_NOT_METERED | 11 | The network traffic is not metered.|
| NET_CAPABILITY_INTERNET  | 12   | The network can connect to the Internet.|
| NET_CAPABILITY_NOT_VPN | 15 | The network does not use a Virtual Private Network (VPN).|
| NET_CAPABILITY_VALIDATED | 16   | The network is available.            |

## NetBearType

Defines the network type.

**System capability**: SystemCapability.Communication.NetManager.Core

| Name        | Value α  | Description       |
| --------------- | ---- | ----------- |
| BEARER_CELLULAR | 0    | Cellular network |
| BEARER_WIFI     | 1    | Wi-Fi network|
| BEARER_ETHERNET | 3 | Ethernet network|

## ConnectionProperties

Defines the network connection properties.

**System capability**: SystemCapability.Communication.NetManager.Core

| Name      | Type                              | Description            |
| ------------- | ---------------------------------- | ---------------- |
| interfaceName | string                             | NIC card name.      |
| domains       | string                             | Domain. The default value is **""**.|
| linkAddresses | Array<[LinkAddress](#linkaddress)> | Link information.      |
| routes        | Array<[RouteInfo](#routeinfo)>     | Route information.      |
| dnses | Array&lt;[NetAddress](#netaddress)&gt; | Network address. For details, see [NetAddress](#netaddress).|
| mtu           | number                             | Maximum transmission unit (MTU).  |

## LinkAddress

Defines network link information.

**System capability**: SystemCapability.Communication.NetManager.Core

| Name      | Type                     | Description                |
| ------------ | ------------------------- | -------------------- |
| address      | [NetAddress](#netaddress) | Link address.          |
| prefixLength | number                    | Length of the link address prefix.|

## RouteInfo

Defines network route information.

**System capability**: SystemCapability.Communication.NetManager.Core

| Name        | Type                       | Description            |
| -------------- | --------------------------- | ---------------- |
| interface      | string                      | NIC card name.      |
| destination    | [LinkAddress](#linkaddress) | Destination IP address.      |
| gateway        | [NetAddress](#netaddress)   | Gateway address.      |
| hasGateway     | boolean                     | Whether a gateway is present.    |
| isDefaultRoute | boolean                     | Whether the route is the default route.|

## NetAddress

Defines the network address.

**System capability**: SystemCapability.Communication.NetManager.Core

| Name | Type  | Description                          |
| ------- | ------ | ------------------------------ |
| address | string | Network address.                        |
| family  | number | Address family identifier. The value is **1** for IPv4 and **2** for IPv6. The default value is **1**.|
| port    | number | Port number. The value range is 0 to 65535.   |