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The reason why the specified path cannot be found when creating a file in java

When creating a file, it prompts that the specified path cannot be found. This is because the directory has not been created. When you create a file, you should first create the file's parent directory and then create the file.

Nov 27, 2019 am 09:23 AM

java document

Java question mark garbled solution

Solution to Java garbled question marks: 1. Convert Chinese encoding format during output (String(str.getBytes("GB2312"), "8859_1");). 2. Convert the encoding format when reading from parameters, the method is opposite to that when outputting.

Nov 27, 2019 am 09:15 AM

java

How to determine whether a string is a decimal in java

The method to determine whether a string is a decimal in "java" is: first, by calling the "isBlank()" method to initially determine whether the string is empty or composed of blank characters, then define a regular expression for judgment, and finally by calling The "matches" method can determine whether a string is a decimal.

Nov 26, 2019 pm 05:42 PM

java judgment string decimal

How to determine what a string starts with in java

The way to determine what a string starts with in "java" is: first define a variable to save the prefix string, and then call the "startsWith" method to determine. If the string starts with the specified prefix, "true" will be returned. Otherwise, "false" is returned.

Nov 26, 2019 pm 05:14 PM

java judgment string beginning

How to determine how many specified characters a string contains in java

The way to determine how many specified characters a string contains in "java" is: first define a variable to save the number of occurrences of the specified character, then call the "indexOf" method to calculate the subscript of the specified character, and finally use "if" Just use the sentence to make a judgment.

Nov 26, 2019 pm 04:56 PM

java judgment character string designation

Characters in java are garbled

The reason why the characters in "java" are garbled is: the characters are garbled due to inconsistency between the encoding method and the decoding method. The solution is: first use the function "defaultCharset" to view the default character set used by the system, and then modify the decoding method to be the same as the encoding method.

Nov 26, 2019 pm 04:45 PM

java Garbled characters character

Introduction to java learning process

Java is a very popular language. Many people are learning Java now. We can easily find many Java tutorials on the Internet, but most of the tutorials we find on the Internet are scattered, which is not conducive to our Java learning. This article will introduce you to the learning process of java.

Nov 26, 2019 pm 04:34 PM

java

How to determine whether a string contains a certain character in java

The method to determine whether a string contains a certain character in "java" is: first, you can use the "contains" method, which returns "true" only if and only if the string contains the specified sequence of character values. Secondly, you can also use "indexOf" method, but the return value of this method is "int".

Nov 26, 2019 pm 04:32 PM

java judgment Include character string

Java collection class graphic tutorial

Java collection classes are the basic knowledge in Java. Collections are mainly responsible for saving and holding other data. Therefore, collection classes are also called container classes. All collection classes are located under the java.util package. This article introduces us to the collection class in Java in detail, hoping to provide some help when you learn Java.

Nov 26, 2019 pm 04:16 PM

java

Detailed explanation of transient keyword in java

Java provides a mechanism for object serialization. An object can be represented by a byte sequence that contains information such as the object's data, the object's type, and the attributes stored in the object. After the byte sequence is written to the file, it is equivalent to persisting the information of an object in the file. Conversely, the byte sequence can also be read back from the file.

Nov 26, 2019 pm 04:14 PM

java transient

How to implement java string formatting and add 0 if the length is insufficient

The method to realize the filling of 0 when the length of string formatting in "java" is insufficient is: first, you can save the length of the string that needs to be formatted into a variable, and then compare it with the required length. If the length is insufficient, further use a "while" loop Judgment, use the "append" function to add 0 to the insufficient part.

Nov 26, 2019 pm 04:11 PM

java string format

How to avoid garbled characters in java programs

The reason why garbled characters appear in the "java" program is that the original encoding format of the string is inconsistent with the encoding format used for parsing when reading. The way to avoid garbled characters is: first, you must know that "java" is uniformly represented by "Unicode" in the string, and then ensure that the string encoding is consistent with the encoding format used for parsing when reading.

Nov 26, 2019 pm 03:55 PM

java Garbled characters

The difference and implementation of 'shallow copy' and 'deep copy' in Java (with code)

Shallow copy, also known as shallow copy. Create a new object, and then copy the non-static fields of the current object to the new object. If the field is of value type, then copy the field; if the field is of reference type, copy the reference but not the referenced object. Deep copy not only copies the object itself, but also copies all objects pointed to by the references contained in the object.

Nov 26, 2019 pm 03:53 PM

java Shallow copy

Java operation database - use connection pool to connect to the database

Create a connection pool and configure connection properties. Use a connection pool to obtain a connection. Every time you need to connect to the database, you do not need to establish a connection, but obtain it through the connection pool, which provides the connection. After using the connection, you do not need to manually release the connection, but let the connection pool release the connection.

Nov 26, 2019 pm 03:31 PM

java connection pool