Findbugs 告诉我，我无缘无故地将非负值与 -1 进行了比较

Question

我有这段代码，它在 FindBugs 中显示以下错误：

Bug: Bad comparison of nonnegative value with -1 in hydra.extensions.drivers.eg2.internal.EG2GatewaySimulator.run()

This code compares a value that is guaranteed to be non-negative with a negative constant or zero. 

Rank: Scary (5), confidence: High
Pattern: INT_BAD_COMPARISON_WITH_NONNEGATIVE_VALUE 
Type: INT, Category: CORRECTNESS (Correctness)

对于代码：

String receivedMessage = "";
char c;
boolean isValidChar;
do {
    c = (char) in.read();
    isValidChar = (c != '\r') && (c != -1);
    if (isValidChar) {
        receivedMessage += c;
    }
} while (isValidChar);

Answer 1

char 的值为 16 位非负值：

char：char 数据类型是单个 16 位 Unicode 字符。它的最小值为 '\u0000'（或 0），最大值为 '\uffff'（或 65,535，含）。

您正在将它与 -1 进行比较。

Findbugs 告诉我，我无缘无故地将非负值与 -1 进行了比较

Findbugs is telling me that I have comparison of nonnegative value with -1 for no apparent reason

java

findbugs