How to use command line tools to debug Java functions?

Using command line tools to debug Java functions requires installing the Java Debugging Tools (JDT), configuring your function, running the function, attaching the debugger, and setting breakpoints in the Java function for debugging.

Debugging Java functions using command line tools

When developing and testing Java functions, debugging is essential for identifying and fixing errors important. Command line tools provide powerful ways to diagnose and debug your functions.

Install Java Debugging Tools

To use command line tools to debug Java functions, you need to install the Java Debugging Tools (JDT). JDT can be downloaded from:

https://marketplace.visualstudio.com/items?itemName=vscjava.vscode-java-debug

Configuring your function

Before debugging a Java function, you need to ensure that your function is configured correctly. The following is to add the necessary dependencies in the pom.xml file:

<dependency>
    <groupId>com.google.cloud</groupId>
    <artifactId>functions-framework-api</artifactId>
    <version>1.0.29</version>
</dependency>

Run the function

To run your function, use the following command:

mvn package appengine:run

This will run your function in the current directory.

Attach Debugger

To attach to a function and set breakpoints while you are debugging it, use the following command:

java -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005 -jar target/function-1.0-SNAPSHOT.jar

This The debug server will be started on port 5005.

Debugging in an IDE

You can attach a debugger to a function using your preferred IDE (such as IntelliJ IDEA or Visual Studio Code). In your IDE, go to Run > Attach to Remote Java Application. In the pop-up window, enter the hostname (localhost) and port number (5005).

Practical case

The following is a practical case of using command line tools to debug Java functions:

import com.google.cloud.functions.HttpFunction;
import com.google.cloud.functions.HttpRequest;
import com.google.cloud.functions.HttpResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.logging.Level;
import java.util.logging.Logger;

public class MyFunction implements HttpFunction {

  private static final Logger logger = Logger.getLogger(MyFunction.class.getName());

  @Override
  public void service(HttpRequest request, HttpResponse response)
      throws IOException {
    try {
      int a = 10;
      int b = 0;

      // 设置断点在这里
      int c = a / b;

      PrintWriter writer = response.getWriter();
      writer.printf("计算的结果是 : %d", c);
    } catch (Exception e) {
      logger.log(Level.SEVERE, "计算失败", e);
      throw e;
    }
  }
}

Running function

To run and debug this function, follow these steps:

1. Run mvn package appengine:run in the terminal.
2. In IDE or use java -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005 -jar target/function-1.0-SNAPSHOT.jar in Attach a debugger from the command line.
3. Access the endpoint of the function. Breakpoints should stop execution at the expected location.
4. Use the debugging features provided by the IDE (such as setting breakpoints, single-stepping, and inspecting variables) to debug your functions.

The above is the detailed content of How to use command line tools to debug Java functions?. For more information, please follow other related articles on the PHP Chinese website!