如何用正则表达式截取字符串，_J2EE

怎么用正则表达式截取字符串，急！！！
字符串如下所示：

U#:zhang_san#:ASSIGN#:2#:0#:0#:0#:#:#:#:#;U#:wang_wu#:ASSIGN#:2#:0#:0#:0#:#:#:#:#;

我想把zhang_san和wang_wu截取出来

------解决方案--------------------

Java code

        String text = "U#:zhang_san#:ASSIGN#:2#:0#:0#:0#:#:#:#:#;U#:wang_wu#:ASSIGN#:2#:0#:0#:0#:#:#:#:#;";        Matcher m = Pattern.compile("U#:([^#]+)#").matcher(text);        StringBuilder sb = new StringBuilder();        while(m.find()){            sb.append(m.group(1)).append(":");        }        if(sb.length()>1)            sb.deleteCharAt(sb.length()-1);        System.out.println(sb.toString());
------解决方案--------------------
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Java code

        String text = "U#:zhang_san#:ASSIGN#:2#:0#:0#:0#:#:#:#:#;U#:wang_wu#:ASSIGN#:2#:0#:0#:0#:#:#:#:#;";
        Matcher m = Pattern.compile("U#:([^#]+)#").matcher(text);
        Strin……