Page 59-JavaBase Programming Tutorials: Learn JavaBase Online-php.cn

Article Tags

Home

Technical Articles

Java

JavaBase

How to execute java (command execution)

Java file execution method: 1. Use "javac+path+x.java" to compile the java file, and use the command "java -cp+path+filename" to execute the java file. 2. Enter the directory where the java file is located, use the command "javac x.java" to compile, and then use the java command to execute.

Nov 25, 2019 am 10:54 AM

java

Summary of Java methods to determine whether a variable is a number

How to determine whether a variable is a number in Java: 1. Use the isDigit() function to determine. 2. First define the regular expression "[0-9]*", and then use matches() to match this regular expression. 3. Use org.apache.commons.lang to judge.

Nov 25, 2019 am 10:34 AM

java

Summary of methods for generating non-repeating random numbers in java

Methods to generate non-repeating random numbers in java: 1. Use ArrayList or array implementation, use the Random() method to generate random numbers and save them in the array, and then deduplicate the array. 2. Use HashSet and HashMap functions to achieve this. These two methods do not allow duplication.

Nov 25, 2019 am 10:24 AM

java

How to determine whether a file exists in java and create a new file if it does not exist

In "java", the method to determine whether a file exists or create a new file if it does not exist is: first save the file path to a file object, and then use the "exists()" method to determine whether the file exists. If it does not exist, use "createNewFile() )" method to create a new file.

Nov 25, 2019 am 10:10 AM

java 判断文件存在

Summary of file downloading and garbled file names in Java

Garbled java download file names can be solved by setting the file name encoding when downloading. In IE browser, you can use the encode() method to specify the encoding format. Files in Java can be downloaded in the form of streams, and files can be read using the FileInputStream method.

Nov 25, 2019 am 10:08 AM

java 文件乱码

The difference between expressions i++ and ++i in java

The difference between the expressions "i++" and "++i" in "java" is: "i++" means assigning a value first and then incrementing; "++i" means incrementing first and then assigning a value. For example: "j=i++" means that the variable "i" is first assigned to the variable "j" and then increments; "j=++i" means that the variable "i" is first incremented and then the variable is assigned a value.

Nov 25, 2019 am 09:59 AM

java i++ ++i 区别

Reasons and solutions for garbled Chinese characters in Java

Java Chinese characters are garbled because the default encoding method in Java is different from the Chinese character encoding method. We only need to convert the encoding format when outputting Chinese characters and reading Chinese characters from parameters. You can use String(str.getBytes("Encoding" ),"encoding"); statement changes the encoding format.

Nov 25, 2019 am 09:42 AM

java

Garbled characters appear when sending emails via java mail

The solution to garbled characters when sending emails using the "mail" package in "java" is: first, specify the text encoding as "GB2312" when sending the body text, then specify the title encoding as "GB2312" when setting the email title, and finally send the body text. Just specify the transfer encoding as "base64" encoding.

Nov 25, 2019 am 09:27 AM

java mail 邮件乱码

How to enter an array from the keyboard in java

The "java" method of inputting an array from the keyboard is: first create an object through the "Scanner" class, then call the "next()" method through this object to obtain the input data, and return the input data by calling the "toString()" method The object value represented, and finally the data is added to the array through a loop.

Nov 23, 2019 pm 04:00 PM

java 键盘输入数组

Java implements uploading pictures to the server

The method of "java" to upload images to the server is: first set the buffer size and temporary file directory, and set the size limit of the uploaded file, then parse the request object to obtain the "List" object of the uploaded content, and determine whether it is an uploaded file. Then call the "write()" method to write the uploaded content to the file.

Nov 23, 2019 pm 03:40 PM

java 实现图片上传服务器

The file name is garbled when java downloads the file

When "java" downloads files, the file name appears garbled. If it is a file name encoding problem, you can encode the file name to "UTF-8" or "ISO". If it is a browser incompatibility problem, you can use "URLEncode" to encode the file name. Encode "UTF-8" or convert bytes to "ISO".

Nov 23, 2019 pm 03:04 PM

java 下载文件乱码

How to verify whether the image verification code is correct in JAVA

The method of verifying the image verification code in "java" is: first, you need to obtain the verification code object entered by the user, and then first determine whether the verification code is empty. If it is not empty, obtain the "toString()" method represented by the verification code. Number" object value, and finally compare the verification code object value with the specified object to determine whether it is correct.

Nov 23, 2019 pm 02:47 PM

java 验证图片验证码

Garbled characters appear when running java projects through bash/cmd

The reason why garbled characters appear when running the "java" project through "bash" or "cmd" is: the default encoding of "cmd" and "bash" is "GBK". The solution is: first set the encoding method of "cmd" to "utf-8" through the "chcp 65001" command, and then specify the encoding parameters when running the project.

Nov 23, 2019 pm 01:56 PM

bash cmd java 运行乱码

How to save files locally in java

The method to save files locally in "java" is: first create a file object according to the file path to be saved, and then use the "exists" method to determine whether the file exists. If it does not exist, create a new file. If it exists, start passing the "FileOutPutStream" ” class creates a new file and writes data to the file.

Nov 23, 2019 pm 01:28 PM

java 实现保存本地