获取异常信息的方法 e.toString() e.getMessage() e.printStackTrace()

public  class TestException(){

@Test
public void test(){

    try{
        throw new IllegalArgumentException("xxxxxx");
    }catch(Exception e){
        System.out.println(e.toString());
        System.out.println();
        System.out.println(e.getMessage());
        System.out.println();
        e.printStackTrace();
    }
}
}

错误信息：

java.lang.IllegalArgumentException: xxxxxx

xxxxxx

java.lang.IllegalArgumentException: xxxxxxx
     at TestException.test(TestException.java:32)

toString() : 打印异常的名称和 创建异常对象时传入的message信息
getMessage(): 打印创建异常对象时传入的message信息
printStackTrace(): 打印 toString，并且输出错误栈信息

toString

 public String toString() {
        String s = getClass().getName();
        String message = getLocalizedMessage();
        return (message != null) ? (s + ": " + message) : s;
    }

 public String getLocalizedMessage() {
        return getMessage();
    }

 public String getMessage() {
        return detailMessage;
    }

  public Throwable(String message) {
        fillInStackTrace();
        detailMessage = message;
    }

printStackTrace()

 private void printStackTrace(PrintStreamOrWriter s) {
        // Guard against malicious overrides of Throwable.equals by
        // using a Set with identity equality semantics.
        Set<Throwable> dejaVu =
            Collections.newSetFromMap(new IdentityHashMap<Throwable, Boolean>());
        dejaVu.add(this);

        synchronized (s.lock()) {
            // Print our stack trace
            s.println(this);          // 调用 toString 
            StackTraceElement[] trace = getOurStackTrace();
            for (StackTraceElement traceElement : trace)   //打印错误栈
                s.println("\tat " + traceElement);

            // Print suppressed exceptions, if any
            for (Throwable se : getSuppressed())
                se.printEnclosedStackTrace(s, trace, SUPPRESSED_CAPTION, "\t", dejaVu);

            // Print cause, if any
            Throwable ourCause = getCause();
            if (ourCause != null)
                ourCause.printEnclosedStackTrace(s, trace, CAUSE_CAPTION, "", dejaVu);
        }
    }