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How to delete files and directories in java

In Java, you can use the "delete()" method to delete files or empty directories. If the file is deleted, it returns "true", otherwise it returns "false". However, when deleting a directory, only empty directories can be deleted successfully, and recursive deletion must be used. all files before the directory can be deleted.

Nov 22, 2019 pm 05:01 PM

java 删除文件目录

How to determine whether a string is empty in java

How to determine whether a string is empty in java: 1. Use str.length()==0 to determine whether the string is empty by determining whether the length of the string is 0. 2. Use the str==null statement to determine whether the string is empty by determining whether the string is null.

Nov 22, 2019 pm 04:55 PM

java

How to set the size of button with picture in Java

The method to set the size of a button with a picture in Java is: first, in the project that requires graphical interface programming in Java, obtain the length and width of the setting button in advance, then use the "getScaledInstance()" method to reconstruct the picture, and then construct the "Icon" The object can be passed into "JButton".

Nov 22, 2019 pm 04:42 PM

java 设置图片按钮大小

How to determine whether a string is a number in java

How to determine whether a string is a number in Java: 1. Traverse a string through a loop, and use the Character.isDigit method in the loop to determine whether the character is a number. 2. Use the regular expression "-?[0-9]+(\\.[0-9]+)?" to determine whether the string is a number.

Nov 22, 2019 pm 04:37 PM

java

How to end if loop in java

The method to end the "if" loop in Java is: first, you can use the "break" statement to end the "if" loop, that is, not to continue executing all subsequent loops, and then you can also use the "continue" statement to end the current loop of the "if" statement. But just ending one level of loop does not affect the continued execution of subsequent loops.

Nov 22, 2019 pm 04:29 PM

java 结束 if 循环

How to assign value to java array

Methods of assigning values to arrays in Java: 1. Use new to specify the size of the array and then assign a value to the array. This method only determines the value when assigning a value to the element. 2. Use new to specify the value of the array element. This method has already determined the value during initialization. 3. Directly specify the value of the array element.

Nov 22, 2019 pm 04:21 PM

java

How to draw simple graphics in java

The method of drawing simple graphics in java is: first we need to import the "Graphics" class into the code. The "Graphics" class will provide a method of drawing a straight line in the coordinate system of the graphics context, and then add member variables for Describe the characteristics of the game area, and finally add a method to draw the game area.

Nov 22, 2019 pm 04:18 PM

java 绘制简单图形

Solve the problem of Chinese garbled file name in java download

Solution to the Chinese garbled file name of Java download: It can be solved by changing the encoding format of the file name. Different browsers have different solutions. 1. In IE browser, filename is UTF8 encoded through URLEncoder. 2. Other browsers convert bytes to ISO8859-1.

Nov 22, 2019 pm 04:06 PM

java

Java determines whether the object is of type string

How to determine whether an object is of string type in Java: 1. Use the instanceof operator to determine whether the object is an instance of the string type. 2. Use getClass to get the type of an instance, and then use getName():String to get the full name of the type to judge.

Nov 22, 2019 pm 03:41 PM

java

Java determines what day it is today

How to determine what day of the week today is in Java: Use the date method to get the day of the week, and then use the Calendar class to get the day of the week. The week obtained by this method starts on Sunday. Or use SimpleDateFormat to format the date to get the day of the week.

Nov 22, 2019 pm 03:19 PM

java

Solution to Java compilation garbled code

Solution to garbled code in java compilation: 1. Add parameters when executing the java compilation command to solve the garbled code. The compilation command: javac -encoding gbk -d Run.java. 2. Modify the language environment configuration of the entire operating system to solve the compilation garbled code.

Nov 22, 2019 pm 02:54 PM

java

Solve the problem of garbled characters when passing Chinese parameters from js to java background

The way to solve the problem of garbled characters when js transmits Chinese parameters to the java backend is: first, we encode the Chinese parameters when passing the value in js, then start to transmit the encoded Chinese parameters to the java backend, and finally the java backend obtains Just decode the Chinese parameters.

Nov 22, 2019 pm 02:38 PM

解决 java 中文参数问题 js

Java post request garbled solution

Solution to the garbled post request in Java: Enter request.setCharacterEncoding("utf-8"); on the requested page to solve the garbled post request. Post requests must be used when uploading files. Post requests have no length limit and are more secure.

Nov 22, 2019 pm 02:37 PM

java 乱码

Does java this access member variables?

In Java, you can use the this keyword to specify the data for accessing member variables. Use this to handle the situation where the member variables and parameter variables in the method have the same name. Use the this keyword in the method definition of the class to represent the reference of the object using the method.

Nov 22, 2019 pm 02:23 PM

java