在java中连接自动生成的字符串，中间有一个空格分隔符
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Concatenate auto generated strings in java with a space seperator in between
提问by user894795
I have a string array variable which values changes continuously. Random arrays are generated from it. This is what i have:
我有一个字符串数组变量，它的值不断变化。从中生成随机数组。这就是我所拥有的：
String trans = Utility.GetColumnValue(testdata[k], "suggest_text_2");
The transvalue changes continuously. How can i concatenate it with the previous values? How can i print every value of transas it changes continuously? Do i need to use any buffer?
该trans值连续变化。如何将它与以前的值连接起来？我如何打印trans不断变化的每个值？我需要使用任何缓冲区吗？
采纳答案by Marco
If you need the intermediate results, you will probably need something like this:
如果你需要中间结果，你可能需要这样的东西：
String yourOldString;
String freshString;
// other code which updates freshString
yourOldString = yourOldString + " " + freshString;
However if you do need to catch all updates but only print out the final result, use a StringBuilder:
但是，如果您确实需要捕获所有更新但只打印出最终结果，请使用 StringBuilder：
private static final String WHITESPACE = " ";
String yourOldString;
String freshString;
StringBuilder builder = new StringBuilder();
builder.append(yourOldString);
// other code which updates freshString
builder.append(WHITESPACE);
builder.append(freshString);
// once everything is done:
String resultString = builder.toString();
回答by Tdorno
System.out.println("string1 "+"string2");
回答by nook
String a = "foo";
String space = " ";
String b = "bar";
String c = a+space+b;
回答by Marvo
It's often best to use StringBuilder to concatenate strings:
通常最好使用 StringBuilder 来连接字符串：
String [] array { "fee", "fie", "foe", "fum" };
boolean firstTime = true;
StringBuilder sb = new StringBuilder(50);
for (String word : array) {
if (firstTime) {
firstTime = false;
} else {
sb.append(' ');
}
sb.append(word);
}
String finalResult = sb.toString();
回答by Blasanka
Simply,
简单地，
String trans = Utility.GetColumnValue(testdata[k], "suggest_text_2");
StringBuffer concat = new StringBuffer();
concat.append(test).append(" ");
Or,
或者，
StringBuffer concat = new StringBuffer();
concat.append(Utility.GetColumnValue(testdata[k], "suggest_text_2")).append(" ");
To concatenate/combine set of data.
连接/组合数据集。
for(String s: trans){
concat.append(s).append(" ");
}
Stringconcatenation(like trans + " ") is slower than the StringBufferappend(). I strongly suggest you to use StringBuilder. Because when combinig Stringon the fly StringBufferis created and then using toString()converts to String.
String连接（如trans + " "）比StringBufferappend(). 我强烈建议你使用StringBuilder. 由于combinig当String在飞行中StringBuffer被创建，然后使用toString()皈依String。
Here is nice blog post to read to learn about performance of these two.
这是不错的博客文章，可以阅读以了解这两者的性能。
