java

Two instances having the same hashcode but not equal

由 |▌冷眼眸甩不掉的悲伤 提交于 2021-02-20 05:52:07
问题 I was reading the paragraph quoted below from an article entitled- Java theory and practice: Hashing it out - Defining hashCode() and equals() effectively and correctly Defining equality The Object class has two methods for making inferences about an object's identity: equals() and hashCode(). In general, if you override one of these methods, you must override both, as there are important relationships between them that must be maintained. In particular, if two objects are equal according to

Two instances having the same hashcode but not equal

由 十年热恋 提交于 2021-02-20 05:52:07
问题 I was reading the paragraph quoted below from an article entitled- Java theory and practice: Hashing it out - Defining hashCode() and equals() effectively and correctly Defining equality The Object class has two methods for making inferences about an object's identity: equals() and hashCode(). In general, if you override one of these methods, you must override both, as there are important relationships between them that must be maintained. In particular, if two objects are equal according to

com.mysql.cj.core.exceptions.InvalidConnectionAttributeException: The server time zone value &#39...

由 限于喜欢 提交于 2021-02-20 05:41:52
<properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> <druid.version>1.0.9</druid.version> <mybatis.boot.starter.version>1.3.0</mybatis.boot.starter.version> <mysql.connector.java.version>8.0.15</mysql.connector.java.version> </properties> datasource: url: jdbc:mysql://localhost:3306/db_pack_case ?useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC username: root password: root driver-class

impala-kudu

由 末鹿安然 提交于 2021-02-20 05:38:02
kkudu 提供了自己的api来对kudu进行操作，但是有的开发人员习惯用jdbc来操作数据库，这里我们采用impala 来实现该功能， impala 安装积配置，请百度，我们的集群采用kerberos认证。 1.jdbc:impala 连接（impala 官方建议连接方式） 官网 下载cloudera-connector zip zip 中的其他jar包我们的集群已经有了，所以只加了ImpalaJDBC41.jar依赖 提交代码所在用户的 principal 是：impala/host@EXAMPLE.COM 连接代码如下： import java.sql.DriverManager val driverName = " com.cloudera.impala.jdbc41.Driver " val url = " jdbc:impala://host:21050;AuthMech=1;KrbRealm=EXAMPLE.COM;KrbHostFQDN=host;KrbServiceName=impala " Class.forName(driverName) val conn = DriverManager.getConnection(url) val prst = conn.prepareStatement( " select * from database.movieas

Alternative class to allow for extensible Strings: How to work around java.lang.String being final? [closed]

由 大城市里の小女人 提交于 2021-02-20 05:35:59
问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 5 days ago . Improve this question Recreating java.lang.String is not hard. See attached code. I'm really writing this to show how easy it is. If anybody wants to figure out how to get the native isBigEndian() and add it in the solutions, that'd be great. Other String methods would be great too. Just put this

Alternative class to allow for extensible Strings: How to work around java.lang.String being final? [closed]

由 夙愿已清 提交于 2021-02-20 05:34:05
问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 5 days ago . Improve this question Recreating java.lang.String is not hard. See attached code. I'm really writing this to show how easy it is. If anybody wants to figure out how to get the native isBigEndian() and add it in the solutions, that'd be great. Other String methods would be great too. Just put this

How to add a function that can compare two tree structure in java?

由 爱⌒轻易说出口 提交于 2021-02-20 05:28:08
问题 I have created a tree data structure, but I am unable to add two methods that can get me those nodes which are different and those nodes which are same. The ** ones are those which are similar nodes and the * ones are different nodes. Tree Structure 1 >23720634 (Root) **24751368** **24751324** **24751324** **23726962** **24751382** **23728776** **23724832** **23727632** **23728875** **23728813** *23722966* **24751324** **17712706** Tree Structure 2 >25764379 (Root) **24751368** **24751324** *

How to compare to List<WebElement> in webdriver?

由 北城以北 提交于 2021-02-20 05:20:48
问题 I am trying to automate Dual list Box testing. I want to compare the selected values(left side) vs moved values (into right side list). Here is the code. Select allFromListData = new Select(listData); // values selection allFromListData.selectByIndex(0); allFromListData.selectByVisibleText("Helena"); List<WebElement> selectedList=allFromListData.getAllSelectedOptions(); //clicking on add button for(int i=0;i<selectedList.size();i++) System.out.println(selectedList.get(i).getText());

Read and Write CSV File using Java

由 落爺英雄遲暮 提交于 2021-02-20 05:14:33
问题 I have a CSV log file and it contains many rows like this: 2016-06-21 12:00:00,000 : helloworld: header1=2;header2=6;header=0 I want to write them to a new CSV file. public void readLogFile() throws Exception { String currentLine = ""; String nextLine = ""; BufferedReader reader = new BufferedReader(new FileReader(file(false))); while ((currentLine = reader.readLine()) != null) { if (currentLine.contains("2016") == true) { nextLine = reader.readLine(); if (nextLine.contains("helloworld") ==

Change JButton focus area

由 左心房为你撑大大i 提交于 2021-02-20 05:14:25
问题 How do i change the area of focus on a JButton so that when i hover my cursor over the button my costume rollover Icon isn't activated slightly before my cursor is over the actual button itself. 回答1: The contains(x, y) method of the button determines when the mouse enters the button. If your custom button is not rectangular then you would need to override this method. Here is an old example that demonstrates this concept: // Old example code found on the internet somewhere // to paint a Round
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