Java常用类库之StringBuffer_stringbuffer sb = new stringbuffer()

StringBuffer

大多数方法与String类似

构造

StringBuffer sb = new StringBuffer();
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public StringBuffer append​(String str)

• 功能：将指定的字符串追加到此字符序列。

StringBuffer sb1 = new StringBuffer("锄禾日当午");
StringBuffer sb2 = sb1.append("，汗滴禾下土");
System.out.println(sb2);
//锄禾日当午，汗滴禾下土
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• 类似方法：
  • public StringBuffer append​(Object obj)
  • public StringBuffer append​(StringBuffer sb)
  • public StringBuffer append​(int i)

public StringBuffer appendCodePoint​(int codePoint)

• 功能：将unicode对应的字符接到字符串末尾

StringBuffer sb1 = new StringBuffer("锄禾日当午");
StringBuffer sb2 = sb1.appendCodePoint(65);
System.out.println(sb2);
//锄禾日当午A
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public StringBuffer reverse()

• 导致此字符序列被序列的反向替换。

StringBuffer sb1 = new StringBuffer("锄禾日当午");
StringBuffer sb2 = sb1.reverse();
System.out.println(sb2);
//午当日禾锄
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public void setCharAt​(int index, char ch)

• 功能：指定索引处的字符设置为ch 。

StringBuffer sb1 = new StringBuffer("锄禾日当午");
sb1.setCharAt(2,'r');
System.out.println(sb1);
//锄禾r当午
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StringBuffer和String的转换 https://www.jb51.net/article/140568.htm