我写了一个 AWS Lambda 处理程序如下:

package com.lambda;
import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.LambdaLogger;
import com.amazonaws.services.lambda.runtime.RequestStreamHandler;
import java.io.*;

public class TestDetailsHandler implements RequestStreamHandler {


    public void  handleRequest(InputStream input,OutputStream output,Context context){

        // Get Lambda Logger
        LambdaLogger logger = context.getLogger();

        // Receive the input from Inputstream throw exception if any

        File starting = new File(System.getProperty("user.dir"));
            System.out.println("Source Location" + starting);

           File cityFile = new File(starting + "City.db");
        FileInputStream fis = null;

        try {
            fis = new FileInputStream(cityFile);

            System.out.println("Total file size to read (in bytes) : "
                    + fis.available());

            int content;
            while ((content = fis.read()) != -1) {
                // convert to char and display it
                System.out.print((char) content);
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fis != null)
                    fis.close();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }

}

它读取一个文件:City.db，在资源文件夹中可用，即使我到处都看到下面:

但它在执行此 lambda 函数时显示以下消息:

START RequestId: 5216ea47-fc43-11e5-96d5-83c1dcdad75d Version: $LATEST
Source Location/
java.io.FileNotFoundException: /city.db (No such file or directory)
    at java.io.FileInputStream.open0(Native Method)
    at java.io.FileInputStream.open(FileInputStream.java:195)
    at java.io.FileInputStream.<init>(FileInputStream.java:138)
    at com.lambda.TestDetailsHandler.handleRequest(TestDetailsHandler.java:26)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at lambdainternal.EventHandlerLoader$StreamMethodRequestHandler.handleRequest(EventHandlerLoader.java:511)
    at lambdainternal.EventHandlerLoader$2.call(EventHandlerLoader.java:972)
    at lambdainternal.AWSLambda.startRuntime(AWSLambda.java:231)
    at lambdainternal.AWSLambda.<clinit>(AWSLambda.java:59)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at lambdainternal.LambdaRTEntry.main(LambdaRTEntry.java:93)
END RequestId: 5216ea47-fc43-11e5-96d5-83c1dcdad75d
REPORT RequestId: 5216ea47-fc43-11e5-96d5-83c1dcdad75d  Duration: 58.02 ms  Billed Duration: 100 ms     Memory Size: 1024 MB    Max Memory Used: 50 MB  

Pom.xml 文件的内容:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.lambda</groupId>
    <artifactId>testdetails</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>test-handler</name>

    <dependencies>
        <dependency>
            <groupId>com.amazonaws</groupId>
            <artifactId>aws-lambda-java-core</artifactId>
            <version>1.1.0</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>



        </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>2.3</version>
                <configuration>
                    <createDependencyReducedPom>false</createDependencyReducedPom>
                </configuration>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

我用过各种方法来到处保存文件，但最后还是没用。能否请您告诉我这里出了什么问题？

但是在我的另一个项目中，我将 xyz.properties 文件保存在资源文件夹中并从 PropertyManager 文件中读取，它工作正常。当我在我的系统上测试它时它工作正常，但在 AWS Lambda 函数上它不起作用。

最佳答案

我对我的代码进行了以下更改，现在它可以完美运行了:

主要更改了以下两行:

类加载器 classLoader = getClass().getClassLoader();

File cityFile = new File(classLoader.getResource("City.db").getFile());

package com.lambda;


import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.LambdaLogger;
import com.amazonaws.services.lambda.runtime.RequestStreamHandler;
import java.io.*;

public class TestDetailsHandler implements RequestStreamHandler {


    public void  handleRequest(InputStream input,OutputStream output,Context context){

        // Get Lambda Logger
        LambdaLogger logger = context.getLogger();

        // Receive the input from Inputstream throw exception if any

        ClassLoader classLoader = getClass().getClassLoader();

        File cityFile = new File(classLoader.getResource("City.db").getFile());
        FileInputStream fis = null;

        try {
            fis = new FileInputStream(cityFile);

            System.out.println("Total file size to read (in bytes) : "
                    + fis.available());

            int content;
            while ((content = fis.read()) != -1) {
                // convert to char and display it
                System.out.print((char) content);
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (fis != null)
                    fis.close();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }

关于java - 如何读取用 Java 编写的 AWS Lambda 函数中的文件？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/36463310/