我找到了许多关于正确使用 EDT 的教程和示例，但是我想听听应该如何反其道而行之：检查一个复杂的应用程序，它有一个 Swing GUI 和许多涉及长网络操作的功能，并找到 EDT 在哪里使用不当。
我发现
SwingUtilities.isEventDispatchThread()
可用于检查一段代码是否在 EDT 内，因此我可以检查所有长操作不会发生在 SwingUtilities.isEventDispatchThread() 返回 true 的地方。
这样对吗？有没有更好的方法可以调试整个应用程序以查找 EDT 的错误使用？谢谢你。
这样对吗？
是的，检查 的值SwingUtilities.isEventDispatchThread()是查看您的代码是否在事件调度线程 (EDT) 上的一种方法。
另一种方法是显示或打印Thread.currentThread().getName(). EDT 几乎总是具有名称“AWT-EventQueue-0”。
这段漂亮的代码来自文章Debugging Swing，最终总结。然而，它不是一个完整的 Swing 调试器。此代码仅检查重绘违规。
文章列出了其他更完善的调试方法。
import javax.swing.JComponent;
import javax.swing.RepaintManager;
import javax.swing.SwingUtilities;
public class CheckThreadViolationRepaintManager extends RepaintManager {
// it is recommended to pass the complete check
private boolean completeCheck = true;
public boolean isCompleteCheck() {
return completeCheck;
}
public void setCompleteCheck(boolean completeCheck) {
this.completeCheck = completeCheck;
}
public synchronized void addInvalidComponent(JComponent component) {
checkThreadViolations(component);
super.addInvalidComponent(component);
}
public void addDirtyRegion(JComponent component, int x, int y, int w, int h) {
checkThreadViolations(component);
super.addDirtyRegion(component, x, y, w, h);
}
private void checkThreadViolations(JComponent c) {
if (!SwingUtilities.isEventDispatchThread()
&& (completeCheck || c.isShowing())) {
Exception exception = new Exception();
boolean repaint = false;
boolean fromSwing = false;
StackTraceElement[] stackTrace = exception.getStackTrace();
for (StackTraceElement st : stackTrace) {
if (repaint && st.getClassName().startsWith("javax.swing.")) {
fromSwing = true;
}
if ("repaint".equals(st.getMethodName())) {
repaint = true;
}
}
if (repaint && !fromSwing) {
// no problems here, since repaint() is thread safe
return;
}
exception.printStackTrace();
}
}
}
检查整个应用程序的 EDT 的正确使用的一种方法是使用 java 代理。下面的代码是发布在Debugging Swing下的代理的改进版本，最终摘要。它适用于 ASM 4.1。创建一个包含 asm-all-4.1.jar（未打包）、已编译代码和将代理指定为 Premain-Class 的清单的 Jar，然后开始。
/**
* A java agent which transforms the Swing Component classes in such a way that a stack
* trace will be dumped or an exception will be thrown when they are accessed from a wrong thread.
*
* To use it, add
* <pre>
* -javaagent:${workspace_loc:MyProject/tool/util/swingEDTCheck}/swingEDTCheck.jar
* </pre>
*
* to the VM arguments of a run configuration. This will cause the stack traces to be dumped.
*
* Use
* <pre>
* -javaagent:${workspace_loc:MyProject/tool/util/swingEDTCheck}/swingEDTCheck.jar=throw
* </pre>
* to throw exceptions.
*
*/
public class SwingEDTCheckAgent {
public static void premain(String args, Instrumentation inst) {
boolean throwing = false;
if ("throw".equals(args)) {
throwing = true;
}
inst.addTransformer(new Transformer(throwing));
}
private static class Transformer implements ClassFileTransformer {
private final boolean throwing;
public Transformer(boolean throwing) {
this.throwing = throwing;
}
@Override
public byte[] transform(ClassLoader loader,
String className,
Class classBeingRedefined,
ProtectionDomain protectionDomain,
byte[] classfileBuffer)
throws IllegalClassFormatException {
// Process all classes in javax.swing package which names start with J
if (className.startsWith("javax/swing/J")) {
ClassReader cr = new ClassReader(classfileBuffer);
ClassWriter cw = new ClassWriter(cr, ClassWriter.COMPUTE_FRAMES);
ClassVisitor cv = new EdtCheckerClassAdapter(cw, throwing);
cr.accept(cv, 0);
return cw.toByteArray();
}
return classfileBuffer;
}
}
private static class EdtCheckerClassAdapter extends ClassVisitor {
private final boolean throwing;
public EdtCheckerClassAdapter(ClassVisitor classVisitor, boolean throwing) {
super(Opcodes.ASM4, classVisitor);
this.throwing = throwing;
}
@Override
public MethodVisitor visitMethod(final int access,
final String name,
final String desc,
final String signature,
final String[] exceptions) {
MethodVisitor mv =
cv.visitMethod(access, name, desc, signature, exceptions);
if (name.startsWith("set") || name.startsWith("get") || name.startsWith("is")) {
return new EdtCheckerMethodAdapter(mv, throwing);
} else {
return mv;
}
}
}
private static class EdtCheckerMethodAdapter extends MethodVisitor {
private final boolean throwing;
public EdtCheckerMethodAdapter(MethodVisitor methodVisitor, boolean throwing) {
super(Opcodes.ASM4, methodVisitor);
this.throwing = throwing;
}
@Override
public void visitCode() {
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/awt/EventQueue", "isDispatchThread", "()Z");
Label l1 = new Label();
mv.visitJumpInsn(Opcodes.IFNE, l1);
Label l2 = new Label();
mv.visitLabel(l2);
if (throwing) {
// more Aggressive: throw exception
mv.visitTypeInsn(Opcodes.NEW, "java/lang/RuntimeException");
mv.visitInsn(Opcodes.DUP);
mv.visitLdcInsn("Swing Component called from outside the EDT");
mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/RuntimeException", "<init>", "(Ljava/lang/String;)V");
mv.visitInsn(Opcodes.ATHROW);
} else {
// this just dumps the Stack Trace
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Thread", "dumpStack", "()V");
}
mv.visitLabel(l1);
}
}
}