javastring如何不拼接null(javastring拼接字符串)

Introduction

Java string is a widely used data type in Java programming language. It is used to represent a sequence of characters. However, when working with Java string, one of the common issues is how to avoid concatenating null values. This article discusses some effective ways to handle this issue.

Using StringUtils from Apache Commons Lang

One of the best ways to deal with null values in Java string is by using StringUtils from Apache Commons Lang. The library provides several methods to check the null value of a string. For instance, StringUtils.isNotBlank() checks if a given string is not null, not empty, not whitespace only. Similarly, StringUtils.isNotEmpty() checks if a given string is not null or not empty. You can use these methods to avoid concatenating nulls in your code.

Using Ternary Operator

Another effective way to avoid concatenating nulls in Java string is by using the ternary operator. The ternary operator is a shorthand way of writing an if-else statement. In this approach, you just need to check if the string is null or not. If the string is null, then you can replace it with an empty string. Here's an example:

String firstName = "John";
String lastName = null;

String fullName = firstName + " " + (lastName != null ? lastName : "");

In this example, we check if the last name is null or not. If it is null, we replace it with an empty string. This approach can be very useful in situations where you need to concatenate multiple strings, and some of them might be null.

Conclusion

Java string is an essential data type in Java programming, and concatenating nulls can lead to unexpected results. The above-discussed methods can help you avoid this issue and write more robust code. By using StringUtils from Apache Commons Lang, you can easily check if a given string is null or not. Additionally, by using the ternary operator, you can handle nulls more efficiently while concatenating multiple strings. Remember to pay attention to null values when working with Java string to avoid any unexpected results.