最近玩android写了个 计算器练手，里面用了一些正则，发现android（2.1）的正则实现与Java的并不完全兼容，看代码：
Java代码
PrintStream textView = System.out; Pattern pattern = null; Matcher matcher = null; String result = null; pattern = Pattern.compile("(?<![a-zA-Z])e(?![a-zA-Z])"); matcher = pattern.matcher("e"); result = matcher.replaceAll("E"); textView.append("replace \"(?<![a-zA-Z])e(?![a-zA-Z])\" with \"e\":\t" + result + "\n\n"); try { //测试否定逆序环视中的无限匹配 pattern = Pattern.compile("(?<!\\d+)e"); matcher = pattern.matcher("e"); result = matcher.replaceAll("E"); textView.append("replace \"(?<!\\d+)e\" with \"e\":\t" + result + "\n\n"); } catch (Exception e) { textView.append("replace \"(?<!\\d+)e\" with \"e\" error:\n" + e + "\n\n"); } try { //测试肯定逆序环视中的无限匹配 pattern = Pattern.compile("(?<=\\d+)e"); matcher = pattern.matcher("e"); result = matcher.replaceAll("E"); textView.append("replace \"(?<=\\d+)e\" with \"e\":\t" + result + "\n\n"); } catch (Exception e) { textView.append("replace \"(?<=\\d+)e\" with \"e\" error:\n" + e + "\n\n"); } try { //测试肯定顺序环视中的无限匹配 pattern = Pattern.compile("(?=\\d+)e"); matcher = pattern.matcher("e"); result = matcher.replaceAll("E"); textView.append("replace \"(?=\\d+)e\" with \"e\":\t" + result + "\n\n"); } catch (Exception e) { textView.append("replace \"(?=\\d+)e\" with \"e\" error:\n" + e + "\n\n"); } try { //测试否定顺序环视中的无限匹配 pattern = Pattern.compile("(?!\\d+)e"); matcher = pattern.matcher("e"); result = matcher.replaceAll("E"); textView.append("replace \"(?!\\d+)e\" with \"e\":\t" + result + "\n\n"); } catch (Exception e) { textView.append("replace \"(?!\\d+)e\" with \"e\" error:\n" + e + "\n\n"); } textView.flush();
android代码：
TextView textView = (TextView)findViewById(R.id.display); Pattern pattern = null; Matcher matcher = null; String result = null; pattern = Pattern.compile("(?<![a-zA-Z])e(?![a-zA-Z])"); matcher = pattern.matcher("e"); result = matcher.replaceAll("E"); textView.append("replace \"(?<![a-zA-Z])e(?![a-zA-Z])\" with \"e\":\t" + result + "\n\n"); try { //测试否定逆序环视中的无限匹配 pattern = Pattern.compile("(?<!\\d+)e"); matcher = pattern.matcher("e"); result = matcher.replaceAll("E"); textView.append("replace \"(?<!\\d+)e\" with \"e\":\t" + result + "\n\n"); } catch (Exception e) { textView.append("replace \"(?<!\\d+)e\" with \"e\" error:\n" + e + "\n\n"); } try { //测试肯定逆序环视中的无限匹配 pattern = Pattern.compile("(?<=\\d+)e"); matcher = pattern.matcher("e"); result = matcher.replaceAll("E"); textView.append("replace \"(?<=\\d+)e\" with \"e\":\t" + result + "\n\n"); } catch (Exception e) { textView.append("replace \"(?<=\\d+)e\" with \"e\" error:\n" + e + "\n\n"); } try { //测试肯定顺序环视中的无限匹配 pattern = Pattern.compile("(?=\\d+)e"); matcher = pattern.matcher("e"); result = matcher.replaceAll("E"); textView.append("replace \"(?=\\d+)e\" with \"e\":\t" + result + "\n\n"); } catch (Exception e) { textView.append("replace \"(?=\\d+)e\" with \"e\" error:\n" + e + "\n\n"); } try { //测试否定顺序环视中的无限匹配 pattern = Pattern.compile("(?!\\d+)e"); matcher = pattern.matcher("e"); result = matcher.replaceAll("E"); textView.append("replace \"(?!\\d+)e\" with \"e\":\t" + result + "\n\n"); } catch (Exception e) { textView.append("replace \"(?!\\d+)e\" with \"e\" error:\n" + e + "\n\n"); }
1、关于第一个例子，原因尚不明确，java可以将e替换为E，而android的替换结果为Ee
2、android的正则实现 不支持在逆序环视中的无限匹配，即使用*或+，可以使用区间量词{n,m},其中m的的最大值不能为Integer.MAX_VALUE,区间的最大值在本例中可为10,11就不行了:(?<!\\d{1,10})e
错误堆栈：
Uncaught handler: thread main exiting due to uncaught exception
java.lang.RuntimeException: Unable to start activity ComponentInfo{freish.activity/fr...
(?<!\d+)e
^
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
at android.app.ActivityThread.access2200(ActivityThread.java:119)atandroid.app.ActivityThread.access2200(ActivityThread.java:119)atandroid.app.ActivityThread.access2200(ActivityThread.java:119)
at android.app.ActivityThreadH.handleMessage(ActivityThread.java:1863)atandroid.app.ActivityThreadH.handleMessage(ActivityThread.java:1863)atandroid.app.ActivityThreadH.handleMessage(ActivityThread.java:1863)
at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123) at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4363) at android.app.ActivityThread.main(ActivityThread.java:4363)
at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521) at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInitMethodAndArgsCaller.run(ZygoteInit.java:860)atcom.android.internal.os.ZygoteInitMethodAndArgsCaller.run(ZygoteInit.java:860)atcom.android.internal.os.ZygoteInitMethodAndArgsCaller.run(ZygoteInit.java:860)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
at dalvik.system.NativeStart.main(Native Method) at dalvik.system.NativeStart.main(Native Method)
Caused by: java.util.regex.PatternSyntaxException: Syntax error U_REGEX_LOOK_BEHIND_L...
(?<!\d+)e
^
at com.ibm.icu4jni.regex.NativeRegEx.open(Native Method) at com.ibm.icu4jni.regex.NativeRegEx.open(Native Method)
at java.util.regex.Pattern.compileImpl(Pattern.java:264) at java.util.regex.Pattern.compileImpl(Pattern.java:264)
at java.util.regex.Pattern.<init>(Pattern.java:239) at java.util.regex.Pattern.<init>(Pattern.java:239)
at java.util.regex.Pattern.compile(Pattern.java:179) at java.util.regex.Pattern.compile(Pattern.java:179)
at freish.activity.RegexActivity.onCreate(RegexActivity.java:28) at freish.activity.RegexActivity.onCreate(RegexActivity.java:28)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
... 11 more ... 11 more
