package com.soft.db; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; /* * 进行Oracle数据库对象的连接操作 */ public class DBConnection { private String username="scott"; private String password="admin"; private String drive="oracle.jdbc.OracleDriver"; pri...
publicclassMain{publicstaticvoidmain(String[]args){// 测试用例String[]testStrings={"",// 空字符串" ",// 仅包含一个空格"\t",// 仅包含一个制表符" ",// 仅包含多个空格"Hello",// 非空字符串" World "// 包含空格的非空字符串};for(Stringtest:testStrings){booleanresult=EmptyStringValidator...
1、s ==null是一定要判断的,而且一定要放到最先判断的位置 2、s.isEmpty() 和 s.length() == 0完全等价 3、要剔除空格,请用 trim()方法 publicvoidtest(String s){//最基本的判空,安全方法if(s ==null|| s.length()== 0){ }//如果说要剔除那些全为空格的字符串,如 s = " ",则用以下方法...
(1) String s1 = "mpptest" (2) String s2 = new String(); (3) String s3 = new String("mpptest") String中常用的方法,用法如图所示,具体问度娘 三个方法的使用: lenth() substring() charAt() package com.mpp.string; public class StringDemo1 { public static void main(String[] args) { ...
In certain scenarios, we need to assert if a givenStringis empty or not. There are quite a few ways to do such assertions in Java. Let’s explore some of those test assertion techniquesin this quick tutorial. 2. Maven Dependencies
public class Test{ public static void main(String [] args) throws Exception{ System.out.println("请输入数字:"); BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); String line=br.readLine(); if(line.matches("\\d+")) //正则表达式 详细见java.util.regex 类 Pattern ...
String s1 = new String("hello"); String s2 = new String("world"); String s3 = s1; System.out.println(s1.length()); //获取字符串长度--输出5 System.out.println(s1.isEmpty()); //判断字符串长度是否为0,即是否为空 } } 在Java中用双引号""引起来的也是String类型对象 ...
// 测试代码publicclassTest{publicstaticvoidmain(String[]args){int i=2;String str="abc";System.out.println(str+i);}}// 反编译后publicclassTest{publicstaticvoidmain(String args[]){byte byte0=10;String s="abc";System.out.println((newStringBuilder()).append(s).append(byte0).toString())...
if (testString==null) { doSomething(); } else { doAnotherThing(); } By default, the doAnotherThing method is called even when the user enters no data, because the testString element has been initialized with the value of an empty string. In order for the Bean Validation model to wo...
mybatis java.lang.NumberFormatException: For input string: "D" 2018-05-10 16:18 −mybatis语句: <if test="status!=null and status=='D' "> , PriorStatus = Status </if> 报错: org.mybatis.spring.MyBatisSystemException: ...