stringbuilder

I am reading in multiple files in with millions of lines and I am creating a list of all line numbers that have a specific issue. For example if a specific field is left blank or contains an invalid value. So my question is what would be the most efficient date type to keep track of a list of numbers that could be upwards of a million number of rows. Would using String Builder, Lists, or something else be more efficient? My end goal is to out put a message like "Specific field is blank on 1-32, 40, 45, 47, 49-51, etc. So in the case of a String Builder, I would check the previous value and if

Can you tell me an easy way to make a string from array of string? I have: String line = "how are you"; string[] split = line.Split(new Char[] { ' ' }); //{"how", "are", "you"} How i can make back "String - How are you"? IT IS ONLY EXAMPLE, NOT REALITY :-) Thank you. Use this: string.Join(" ", split); 来源： https://stackoverflow.com/questions/26315748/c-sharp-how-do-i-make-string-from-array-of-string

Java 基础部分 1. JDK 和 JRE 有什么区别？ JDK：Java Development Kit 的简称，java 开发工具包，提供了 java 的开发环境和运行环境。 JRE：Java Runtime Environment 的简称，java 运行环境，为 java 的运行提供了所需环境。 具体来说 JDK 其实包含了 JRE，同时还包含了编译 java 源码的编译器 javac，还包含了很多 java 程序调试和分析的工具。简单来说：如果你需要运行 java 程序，只需安装 JRE 就可以了，如果你需要编写 java 程序，需要安装 JDK。 2. == 和 equals 的区别是什么？ == 解读 对于基本类型和引用类型 == 的作用效果是不同的，如下所示： 基本类型：比较的是值是否相同； 引用类型：比较的是引用是否相同； 代码示例： 1 String x = "string"; 2 String y = "string"; 3 String z = new String("string"); 4 System.out.println(x==y); // true 5 System.out.println(x==z); // false 6 System.out.println(x.equals(y)); // true 7 System.out.println

读了一点源码，很浅的那种，有些东西觉得很有趣，记录一下。 1.ArrayList的本质是Object[] public ArrayList(int initialCapacity) { if (initialCapacity > 0) { this.elementData = new Object[initialCapacity]; } else if (initialCapacity == 0) { this.elementData = EMPTY_ELEMENTDATA; } else { throw new IllegalArgumentException("Illegal Capacity: "+ initialCapacity); } } 　　 2.HashSet的本质是HashMap public HashSet() { map = new HashMap<>(); } 　　 3.String的本质是final类型的char[] private final char value[]; public String() { this.value = "".value; } public String(String original) { this.value = original.value; this.hash = original.hash; } public

I have a (large) template and want to replace multiple values. The replacement needs to be done case insensitive. It must also be possible to have keys that does not exist in the template. For example: [TestMethod] public void ReplaceMultipleWithIgnoreCaseText() { const string template = "My name is @Name@ and I like to read about @SUBJECT@ on @website@, tag @subject@"; const string expected = "My name is Alex and I like to read about C# on stackoverflow.com, tag C#"; var replaceParameters = new List<KeyValuePair<string, string>> { new KeyValuePair<string, string>("@name@","Alex"), new

StringBuffer 和 StringBuilder 类 当对字符串进行修改的时候，需要使用 StringBuffer 和 StringBuilder 类。 和 String 类不同的是，StringBuffer 和 StringBuilder 类的对象能够被多次的修改，并且不产生新的未使用对象。 StringBuilder 类在 Java 5 中被提出，它和 StringBuffer 之间的最大不同在于 StringBuilder 的方法不是线程安全的（不能同步访问）。 由于 StringBuilder 相较于 StringBuffer 有速度优势，所以多数情况下建议使用 StringBuilder 类。然而在应用程序要求线程安全的情况下，则必须使用 StringBuffer 类。 Test.java 文件代码： public class Test{ public static void main(String args[]){ StringBuffer sBuffer = new StringBuffer("菜鸟教程官网："); sBuffer.append("www"); sBuffer.append(".runoob"); sBuffer.append(".com"); System.out.println(sBuffer); } } 以上实例编译运行结果如下：

注： 该集成方式，对Elasticsearch无版本限制，但是需要自行封装请求，解析结果等。 <dependency> <groupId>org.elasticsearch.client</groupId> <artifactId>elasticsearch-rest-client</artifactId> <version>7.3.0</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.47</version> </dependency> 客户端配置RestConfig @Configuration public class RestConfig { @Bean public RestClient getClient() throws KeyStoreException, NoSuchAlgorithmException, KeyManagementException { // 如果有多个从节点可以持续在内部new多个HttpHost，参数1是ip,参数2是HTTP端口，参数3是通信协议 RestClientBuilder clientBuilder = RestClient.builder(new