There was a problem with the gadget made before. From time to time, it reported that the array exceeded the boundary, but the specific code could not be located.

Take some time to solve it today.

The effect you want to achieve is like this: multiple threads display messages on the textarea in turn. In order to ensure real-time data update, you need to constantly refresh the textarea component.

The original code is like this

    public void refresh() {
        if(currentServerName == null) {
            //Refuse to refresh
            return;
        }
        setText("");
        appendText(LOG_MAP.getOrDefault(currentServerName, ""));
        setScrollTop(Double.MAX_VALUE);
        
    }

Directly refresh the data in the textarea in an external thread (a thread created by yourself).

After consulting the data, it is found that the container content must be modified in JavaFX’s own thread to ensure that no error will be reported. So wrap it with the platform. The modified code is as follows:

    public void refresh() {
        if(currentServerName == null) {
            //Refuse to refresh
            return;
        }
        setText("");
        appendText(LOG_MAP.getOrDefault(currentServerName, ""));
        setScrollTop(Double.MAX_VALUE);
        Platform.runLater(()->{
            setText("");
            appendText(LOG_MAP.getOrDefault(currentServerName, ""));
            setScrollTop(Double.MAX_VALUE);
        });
    }

Java 9 reflection error

Problem solving

Question

when writing JavaFX, perform the HTTP request database login operation, and convert the returned JSON string into a class object. The following code always reports an error.

// json string to class object
JavaType javaType;
ResponseBean<T> data = new ObjectMapper().readValue(json, javaType);

the following errors are reported:

java.lang.reflect.InaccessibleObjectException: Unable to make protected cc.nsurl.bean.ResponseBean() accessible: module cc.nsurl.controllers does not "opens cc.nsurl.bean" to module com.fasterxml.jackson.databind

if you can’t open the class, you can’t reflect.

Solution:

Add the file module-info.java to the JavaFX project. The overall project structure is as follows:

-- src
   -- main
       -- java
          -- module-info.java

Configure in this java file:

module cc.nsurl.controllers {
    // Classes that require reflection opens Self-written classes to third-party libraries
    opens cc.nsurl.controllers to javafx.fxml;
    opens cc.nsurl.bean to com.fasterxml.jackson.databind;
    exports cc.nsurl.controllers;
}