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# 调用、列出和删除 AWS Lambda 函数
本节提供了使用 适用于 Java 的 AWS SDK 2.x 使用 Lambda 服务客户端进行编程的示例。
**Topics**
+ [调用 Lambda 函数](#invoke-function)
+ [列出 Lambda 函数](#list-function)
+ [删除 Lambda 函数](#delete-function)
## 调用 Lambda 函数
您可以通过创建[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)对象并调用其`invoke`方法来调用 Lambda 函数。创建一个[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)对象以指定其他信息，例如要传递给函数的函数名称和有效负载。 Lambda 函数名称显示为 *arn: aws: lambda: us-east-1:123456789012:* function:。HelloFunction可以通过查看 AWS 管理控制台中的函数来检索值。
要将有效载荷数据传递给函数，请创建包含信息的 [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) 对象。例如，在以下代码示例中，请注意传递给 Lambda 函数的 JSON 数据。
**导入**
```
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;
```
**代码**
以下代码示例演示了如何调用 Lambda 函数。
```
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);
}
}
```
请参阅上的[完整示例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/f807d60010caf3d14fe4cd0801b842fb8e9511ca/javav2/example_code/lambda/src/main/java/com/example/lambda/LambdaInvoke.java) GitHub。
## 列出 Lambda 函数
构建一个 `[Lambda Client](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/lambda/LambdaClient.html)` 对象并调用其 `listFunctions` 方法。此方法返回一个 [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) 对象。您可以调用此对象的 `functions` 方法以返回 [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) 对象的列表。可以遍历该列表来检索有关函数的信息。例如，以下 Java 代码示例说明如何获取每个函数名称。
**导入**
```
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;
```
**代码**
以下 Java 代码示例演示如何检索 函数名称的列表。
```
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);
}
}
```
请参阅上的[完整示例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/f807d60010caf3d14fe4cd0801b842fb8e9511ca/javav2/example_code/lambda/src/main/java/com/example/lambda/ListLambdaFunctions.java) GitHub。
## 删除 Lambda 函数
构建一个 [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) 对象并调用其 `deleteFunction` 方法。创建一个 [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) 对象并将其传递给 `deleteFunction` 方法。此对象包含要删除的函数的名称等信息。函数名称显示为 *arn: aws: lambda: us-east-1:123456789012:* function:。HelloFunction可以通过查看 AWS 管理控制台中的函数来检索值。
**导入**
```
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;
```
**代码**
以下 Java 代码演示了如何删除 Lambda 函数。
```
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);
}
}
```
请参阅上的[完整示例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/f807d60010caf3d14fe4cd0801b842fb8e9511ca/javav2/example_code/lambda/src/main/java/com/example/lambda/DeleteFunction.java) GitHub。