Why Does My Java String `replace()` Method Not Seem to Work?-javaTutorial-php.cn

Why Does My Java String `replace()` Method Not Seem to Work?

Patricia Arquette

Release： 2024-11-19 21:59:03

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Why Does My Java String `replace()` Method Not Seem to Work?

Java String replace Method Failure [Duplicate]

Certain Java implementations have reported the replace() method failing to adequately replace specific strings within a given String. This anomaly occurs due to the immutable nature of String objects.

Analysis of the Problematic Code:

In the provided code snippet:

<br>String delimiter = "<em></em>";<br>String html = "<html><head></head><body><strong>USERNAME</strong> AND <strong>PASSWORD</strong></body></html>";<br>Map<String, String> mp = new HashMap<String, String>();<br>mp.put("USERNAME", "User A");<br>mp.put("PASSWORD", "B");<br>for (Entry<String, String> entry : mp.entrySet()) {<br>  html.replace(delimiter   entry.getKey()  delimiter, entry.getValue());<br>}<br>

Explanation of the Issue:

The replace() method in Java does not mutate the original String object. Instead, it returns a new String with the replacements applied. This is the point of contention: the original html variable continues to hold the original String value.

Resolution:

To rectify this, the code should be modified to explicitly reassign the html variable with the result of the replace() operation:

<br>html = html.replace(delimiter   entry.getKey()  delimiter, entry.getValue());<br>

Conclusion:

Understanding the immutability of String objects is crucial when utilizing methods like replace(). Assigning the returned String object to the original variable ensures the intended replacements take effect.

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