转换 JAVA 流抛出 IllegalStateException: Duplicate key [duplicate]

Question

前段时间有人问过这个question：

输入字符串：utilMapString = "1=1,2=2,3=3,4=4,5=5"

Map<String, String> reconstructedUtilMap = Arrays.stream(utilMapString.split(","))
            .map(s -> s.split("="))
            .collect(Collectors.toMap(s -> s[0], s -> s[1]));

如果我将输入更改为“101|Google,102|Amazon”并执行相同的转换，代码会抛出 IllegalStateException: Duplicate key

Map<String, String> reconstructedUtilMap = Arrays.stream(utilMapString.split(","))
                .map(s -> s.split("|", 2))
                .collect(Collectors.toMap(s -> s[0], s -> s[1]));

谁能解释一下这两组操作的确切区别。

Answer 1

您需要在第二个split() 调用中转义管道字符。像这样：

Map<String, String> reconstructedUtilMap = Arrays.stream("101|Google,102|Amazon" .split(","))
                .map(s -> s.split("\\|"))
                .collect(Collectors.toMap(s -> s[0], s -> s[1]));