publicclassStringTruncationExample{publicstaticvoidmain(String[]args){StringinputString="This is a long string that needs to be truncated.";intmaxLength=10;StringtruncatedString=truncateString(inputString,maxLength);System.out.println("原始字符串: "+inputString);System.out.println("截断后的字符串: "...
下面是一个简单的Java方法,用来截取固定字节长度的字符串: publicstaticStringtruncateString(Stringstr,intlength){intbytes=0;StringBuildersb=newStringBuilder();for(charc:str.toCharArray()){bytes+=String.valueOf(c).getBytes().length;if(bytes>length){break;}sb.append(c);}returnsb.toString();} 1. 2...
Truncate a String to the given length with no warnings or error raised if it is bigger. @param value String to be truncated @param length Maximum length of string @return Returns value if value is null or value.length() is less or equal to than length, otherwise a String representing val...
一般而言,drop > truncate > delete 应用范围。TRUNCATE 只能对TABLE;DELETE可以是table和view TRUNCATE 和DELETE只删除数据,而DROP则删除整个表(结构和数据)。 truncate与不带where的delete :只删除数据,而不删除表的结构(定义)drop语句将删除表的结构被依赖的约束(constrain),触发器(trigger)索引(index);依赖于该表...
delete属于DML语言,需要事务管理,commit之后才能生效。drop和truncate属于DDL语言,操作立刻生效,不可回滚。 使用场合: 当你不再需要该表时,用 drop;当你仍要保留该表,但要删除所有记录时,用 truncate;当你要删除部分记录时(always with a where clause), 用 delete。
TRUNCATE:用于删除表中的所有记录,但不删除表结构。 TRUNCATE TABLE employees; 数据操作语言(DML) DML包括用于添加、删除、更新和查询数据的命令。 INSERT INTO:用于向表中插入新记录。 INSERT INTO employees (employee_id, first_name, last_name, birth_date, email, hire_date) VALUES (10, 'John', 'Doe...
18.删除一张表中所有数据的方式?1.truncate 删除内容,不删除定义,释放空间 2.delete 删除内容,不删除定义,不释放空间 truncate 比 delete 速度快,且使用的系统和事务日志资源少。delete 语句每次删除一行,并在事务日志中为所删除的每行记录一项。 19.索引(index)相当于书签,能够提高数据的访问效率 注:主键列自动...
String sql="truncate table "+tableName; stmt.execute(sql); log.info("truncated table:"+tableName); }/*** 向一个表插入数据 *@paramtableName *@paramcount *@paraminnerArr *@paramconn *@paramstmt *@throwsSQLException*/privatevoidinsertTestDataTo()throwsSQLException{//得到字段名和字段类型List<...
truncateString(Collection coll, int cLimit) Provide a string representation of elements within the collection until the concatenated string length exceeds cLimit. static String truncateString(String s, int cLimit) Truncate a string to the specified character count. static void wait(Object o, long ...
SetString(Int64, String) Writes the given Java String to the CLOB value that this Clob object designates at the position pos. (Inherited from IClob) Truncate(Int64) Truncates the CLOB value that this Clob designates to have a length of len characters. (Inherited from IClob) Unregister...