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# 叫用、列出和刪除 AWS Lambda 函數
本節提供使用 適用於 Java 的 AWS SDK 2.x 搭配 Lambda 服務用戶端進行程式設計的範例。
**Topics**
+ [叫用 Lambda 函數。](#invoke-function)
+ [列出 Lambda 函數](#list-function)
+ [刪除 Lambda 函數](#delete-function)
## 叫用 Lambda 函數。
您可以透過建立[https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/LambdaClient.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/LambdaClient.html)物件並叫用其`invoke`方法來叫用 Lambda 函數。建立 [https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/model/InvokeRequest.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/model/InvokeRequest.html) 物件以指定其他資訊，例如函數名稱和要傳遞給 Lambda 函數的承載。函數名稱會顯示為 *arn：aws：lambda：us-east-1：123456789012：function：HelloFunction*。您可以查看 中的 函數來擷取值 AWS 管理主控台。
若要將承載資料傳遞至函數，請建立包含資訊的[https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/core/SdkBytes.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/core/SdkBytes.html)物件。例如，在以下的程式碼範例中，請注意傳遞至 Lambda 函數的 JSON 資料。
**匯入**
```
import software.amazon.awssdk.services.lambda.LambdaClient;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.lambda.model.InvokeRequest;
import software.amazon.awssdk.core.SdkBytes;
import software.amazon.awssdk.services.lambda.model.InvokeResponse;
import software.amazon.awssdk.services.lambda.model.LambdaException;
```
**Code**
下列程式碼範例示範如何叫用 Lambda 函數。
```
public static void invokeFunction(LambdaClient awsLambda, String functionName) {
InvokeResponse res = null ;
try {
//Need a SdkBytes instance for the payload
String json = "{\"Hello \":\"Paris\"}";
SdkBytes payload = SdkBytes.fromUtf8String(json) ;
//Setup an InvokeRequest
InvokeRequest request = InvokeRequest.builder()
.functionName(functionName)
.payload(payload)
.build();
res = awsLambda.invoke(request);
String value = res.payload().asUtf8String() ;
System.out.println(value);
} catch(LambdaException e) {
System.err.println(e.getMessage());
System.exit(1);
}
}
```
請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/f807d60010caf3d14fe4cd0801b842fb8e9511ca/javav2/example_code/lambda/src/main/java/com/example/lambda/LambdaInvoke.java)。
## 列出 Lambda 函數
建置`[Lambda Client](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/LambdaClient.html)`物件並叫用其`listFunctions`方法。此方法會傳回[https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/model/ListFunctionsResponse.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/model/ListFunctionsResponse.html)物件。您可以叫用此物件的 `functions`方法，以傳回[https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/model/FunctionConfiguration.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/model/FunctionConfiguration.html)物件清單。您可以逐一查看清單以擷取函數的相關資訊。例如，下列 Java 程式碼範例示範如何取得每個函數名稱。
**匯入**
```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.lambda.LambdaClient;
import software.amazon.awssdk.services.lambda.model.LambdaException;
import software.amazon.awssdk.services.lambda.model.ListFunctionsResponse;
import software.amazon.awssdk.services.lambda.model.FunctionConfiguration;
import java.util.List;
```
**Code**
下列 Java 程式碼範例示範如何擷取函數名稱清單。
```
public static void listFunctions(LambdaClient awsLambda) {
try {
ListFunctionsResponse functionResult = awsLambda.listFunctions();
List list = functionResult.functions();
for (FunctionConfiguration config: list) {
System.out.println("The function name is "+config.functionName());
}
} catch(LambdaException e) {
System.err.println(e.getMessage());
System.exit(1);
}
}
```
請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/f807d60010caf3d14fe4cd0801b842fb8e9511ca/javav2/example_code/lambda/src/main/java/com/example/lambda/ListLambdaFunctions.java)。
## 刪除 Lambda 函數
建置[https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/LambdaClient.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/LambdaClient.html)物件並叫用其`deleteFunction`方法。建立[https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/model/DeleteFunctionRequest.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/model/DeleteFunctionRequest.html)物件並將其傳遞至 `deleteFunction`方法。此物件包含資訊，例如要刪除的函數名稱。函數名稱會顯示為 *arn：aws：lambda：us-east-1：123456789012：function：HelloFunction*。您可以查看 中的 函數來擷取值 AWS 管理主控台。
**匯入**
```
import software.amazon.awssdk.services.lambda.LambdaClient;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.lambda.model.DeleteFunctionRequest;
import software.amazon.awssdk.services.lambda.model.LambdaException;
```
**Code**
下列 Java 程式碼示範如何刪除 Lambda 函數。
```
public static void deleteLambdaFunction(LambdaClient awsLambda, String functionName ) {
try {
DeleteFunctionRequest request = DeleteFunctionRequest.builder()
.functionName(functionName)
.build();
awsLambda.deleteFunction(request);
System.out.println("The "+functionName +" function was deleted");
} catch(LambdaException e) {
System.err.println(e.getMessage());
System.exit(1);
}
}
```
請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/f807d60010caf3d14fe4cd0801b842fb8e9511ca/javav2/example_code/lambda/src/main/java/com/example/lambda/DeleteFunction.java)。