stringbuilder

问题 Here's some simple Java code: String s = new StringBuilder().append("a").append("b").append("c").toString(); I compile it with JRE 1.6, and I observe the following in the decompiled class file: String s = "a" + "b" + "c"; I had the following questions: Why does the compiler choose '+' over StringBuilder? Do we have any official Java specification that justifies this behavior? Does it really make sense to use StringBuilder in such cases, where we know compiler is going to change it anyway? 回答1

问题 Here's some simple Java code: String s = new StringBuilder().append("a").append("b").append("c").toString(); I compile it with JRE 1.6, and I observe the following in the decompiled class file: String s = "a" + "b" + "c"; I had the following questions: Why does the compiler choose '+' over StringBuilder? Do we have any official Java specification that justifies this behavior? Does it really make sense to use StringBuilder in such cases, where we know compiler is going to change it anyway? 回答1

问题 I am in big trouble, created a hashMap and inserted two values with same key using StringBuilder as a key of map. Now, while trying to retrieve the data using StringBuilder object is working fine, but in other case its fails to return any value. I have listed three cases in the below given code, ` class MainClass { public static void main(String[] args) { MainClass m = new MainClass(); StringBuilder sb = new StringBuilder("sb"); StringBuilder sb1 = new StringBuilder("sb"); Map<StringBuilder,

问题 I am in big trouble, created a hashMap and inserted two values with same key using StringBuilder as a key of map. Now, while trying to retrieve the data using StringBuilder object is working fine, but in other case its fails to return any value. I have listed three cases in the below given code, ` class MainClass { public static void main(String[] args) { MainClass m = new MainClass(); StringBuilder sb = new StringBuilder("sb"); StringBuilder sb1 = new StringBuilder("sb"); Map<StringBuilder,

问题 I am in big trouble, created a hashMap and inserted two values with same key using StringBuilder as a key of map. Now, while trying to retrieve the data using StringBuilder object is working fine, but in other case its fails to return any value. I have listed three cases in the below given code, ` class MainClass { public static void main(String[] args) { MainClass m = new MainClass(); StringBuilder sb = new StringBuilder("sb"); StringBuilder sb1 = new StringBuilder("sb"); Map<StringBuilder,

问题 The following returns nothing for me in eclipse, is this expected behaviour ? StringBuilder sb = new StringBuilder(""); for(int i = 0; i < 256*256*2*6; i++) { sb.append("a"); } System.out.println(sb.toString()); The code returns without error and the size is well withhin memory capacity unlike in Maximum number of characters stringbuilder can accommodate Solved: The problem lies in the eclipse console and enabling (Window -> Preferences -> Run/Debug -> Console -> fixed width console) will

问题 This question already has answers here : Yet again on string append vs concat vs + (6 answers) Closed 10 months ago . Am trying to append multiple strings in StringBuilder, is there any major difference using String str1 = "some"; String str2 = "string"; Now, sb.append(str1).append(str2); // using chained appends and using sb.append(str1 + str2); // using '+' operator My IDE suggests me to use the first method, is there difference between them regarding being thread safe or something like

来源： https://stackoverflow.com/questions/25274894/c-sharp-string-substring-equivalent-for-stringbuilder

来源： https://stackoverflow.com/questions/25274894/c-sharp-string-substring-equivalent-for-stringbuilder

来源： https://stackoverflow.com/questions/25274894/c-sharp-string-substring-equivalent-for-stringbuilder