运行中获取当前执行位置所在类、所在函数等信息

目的：为方便Debug，需要在运行时确定当前执行位置的上下文信息，如确定当前执行代码所在类、所在文件，所在函数、所在行等。

思路：

1、使用Java的栈跟踪API。

2、使用类反射机制。

具体实现：

思路1:

代码示例：

/* Utility class: Getting the name of the current executing method
* http://stackoverflow.com/questions/442747/getting-the-name-of-the-current-executing-method *
* Provides:
*
*      getCurrentClassName()
*      getCurrentMethodName()
*      getCurrentFileName()
*
*      getInvokingClassName()
*      getInvokingMethodName()
*      getInvokingFileName()
*
* Nb. Using StackTrace's to get this info is expensive. There are more optimised ways to obtain
* method names. See other stackoverflow posts eg. http://stackoverflow.com/questions/421280/in-java-how-do-i-find-the-caller-of-a-method-using-stacktrace-or-reflection/2924426#2924426 *
* 29/09/2012 (lem) - added methods to return (1) fully qualified names and (2) invoking class/method names
*/

public class StackTraceInfo {
/* (Lifted from virgo47's stackoverflow answer) */
private static final int CLIENT_CODE_STACK_INDEX;

static {
// Finds out the index of "this code" in the returned stack trace -
// funny but it differs in JDK 1.5 and 1.6
int i = 0;
for (StackTraceElement ste : Thread.currentThread().getStackTrace()) {
i++;
if (ste.getClassName().equals(StackTraceInfo.class.getName())) {
break;
}
}
CLIENT_CODE_STACK_INDEX = i;
}

public static String getCurrentMethodName() {
return getCurrentMethodName(1); // making additional overloaded method
// call requires +1 offset
}

private static String getCurrentMethodName(int offset) {
return Thread.currentThread().getStackTrace()[CLIENT_CODE_STACK_INDEX
+ offset].getMethodName();
}

public static String getCurrentClassName() {
return getCurrentClassName(1); // making additional overloaded method
// call requires +1 offset
}

private static String getCurrentClassName(int offset) {
return Thread.currentThread().getStackTrace()[CLIENT_CODE_STACK_INDEX
+ offset].getClassName();
}

public static String getCurrentFileName() {
return getCurrentFileName(1); // making additional overloaded method
// call requires +1 offset
}

private static String getCurrentFileName(int offset) {
String filename = Thread.currentThread().getStackTrace()[CLIENT_CODE_STACK_INDEX
+ offset].getFileName();
int lineNumber = Thread.currentThread().getStackTrace()[CLIENT_CODE_STACK_INDEX
+ offset].getLineNumber();

return filename + ":" + lineNumber;
}

public static String getInvokingMethodName() {
return getInvokingMethodName(2);
}

private static String getInvokingMethodName(int offset) {
return getCurrentMethodName(offset + 1); // re-uses
// getCurrentMethodName()
// with desired index
}

public static String getInvokingClassName() {
return getInvokingClassName(2);
}

private static String getInvokingClassName(int offset) {
return getCurrentClassName(offset + 1); // re-uses getCurrentClassName()
// with desired index
}

public static String getInvokingFileName() {
return getInvokingFileName(2);
}

private static String getInvokingFileName(int offset) {
return getCurrentFileName(offset + 1); // re-uses getCurrentFileName()
// with desired index
}

public static String getCurrentMethodNameFqn() {
return getCurrentMethodNameFqn(1);
}

private static String getCurrentMethodNameFqn(int offset) {
String currentClassName = getCurrentClassName(offset + 1);
String currentMethodName = getCurrentMethodName(offset + 1);

return currentClassName + "." + currentMethodName;
}

public static String getCurrentFileNameFqn() {
String CurrentMethodNameFqn = getCurrentMethodNameFqn(1);
String currentFileName = getCurrentFileName(1);

return CurrentMethodNameFqn + "(" + currentFileName + ")";
}

public static String getInvokingMethodNameFqn() {
return getInvokingMethodNameFqn(2);
}

private static String getInvokingMethodNameFqn(int offset) {
String invokingClassName = getInvokingClassName(offset + 1);
String invokingMethodName = getInvokingMethodName(offset + 1);

return invokingClassName + "." + invokingMethodName;
}

public static String getInvokingFileNameFqn() {
String invokingMethodNameFqn = getInvokingMethodNameFqn(2);
String invokingFileName = getInvokingFileName(2);

return invokingMethodNameFqn + "(" + invokingFileName + ")";
}
}

思路2：

实例代码：

String methodName = new Object(){}.getClass().getEnclosingMethod().getName();
String packageName = new Object(){}.getClass().getPackage().getName();

参考资料：

1、Getting the name of the current executing method