StringBuilder insert(int offset, float f) StringBuilder insert(int offset, double d) StringBuilder insert(int offset, char c) StringBuilder insert(int offset, char[] ch) StringBuilder insert(int offset, char[] str, int strOffset, int strLen) StringBuilder insert(int offset, String str) StringBui...
importjava.io.*;publicclassInsertDataAtBeginningOfFile{publicstaticvoidmain(String[]args){StringfilePath="example.txt";StringnewData="New data to insert\n";try{Filefile=newFile(filePath);BufferedReaderreader=newBufferedReader(newFileReader(file));StringBuildersb=newStringBuilder();Stringline=reader.rea...
Returns the index within this string of the first occurrence of the specified substring, starting at the specified index. StringBuilder insert(int offset, boolean b) Inserts the string representation of the boolean argument into this sequence. StringBuilder insert(int offset, char c) Inserts the...
StringBuilderDemo.java package com.yiibai.tutorial.strbb; public class StringBuilderDemo { public static void main(String[] args) { // Create StringBuilder object // with no characters in it and // an initial capacity specified by the capacity argument StringBuilder sb = new StringBuilder(10); ...
StringBuilder appendCodePoint(int cp) 追加一个码点,并将其转换为一个或两个代码单元并返回this void setCharAt(int i, char c) 将第i个代码单元设置为c StringBuilder insert(int offset, String str) 在offset位置插入一个字符串并返回this StringBuilder insert(int offset, char c) ...
As of release JDK 5, this class has been supplemented with an equivalent class designed for use by a single thread, StringBuilder. The StringBuilder class should generally be used in preference to this one, as it supports all of the same operations but it is faster, as it performs no synch...
1.insert前select 插入数据前先根据某一字段查询一下数据库,如果已经存在就修改,不存在再插入。 2.加锁 加锁可解决一切问题,但也要考虑并发性。 主要包括悲观锁,乐观锁,分布式锁。 悲观锁的并发性较低,更适合使用在防止数据重复的场景,注意幂等性不光是防止重复还需要结果相同。
[Android.Runtime.Register("append", "(Ljava/lang/CharSequence;II)Ljava/lang/StringBuilder;", "")] public override Java.Lang.IAppendable Append (Java.Lang.ICharSequence? s, int start, int end); Parameters s ICharSequence start Int32 the beginning index. end Int32 the ending index. ...
java.io包包含一个“PrintStream”类,该类有两种格式方法,可以用来替换“print”和“println”。这些方法“format”和“printf”彼此等效。熟悉的“系统”。out”恰好是“PrintStream”对象,因此您可以在“System.out”上调用“PrintStream”方法。因此,您可以在代码中以前使用过“print”或“println”的任何地方使用“for...
public <T> StringBuilderPlus append(T t) { stringBuilder.append(t); return this; } public <T> StringBuilderPlus appendLine(T t) { stringBuilder.append(t).append(System.lineSeparator()); return this; } @Override public String toString() { ...