android正则并不完全兼容java正则

freish 发布于 2012/05/18 16:38
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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.access$2200(ActivityThread.java:119) at android.app.ActivityThread.access$2200(ActivityThread.java:119) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863) 
at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:123) at android.os.Looper.loop(Looper.java:123) 
at android.app.ActivityThread.main(ActivityThread.java:4363) at android.app.ActivityThread.main(ActivityThread.java:4363) 
at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:521) at java.lang.reflect.Method.invoke(Method.java:521) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.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 



3、无论是java还是android,顺序环视都可以支持无限匹配

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