[英]Can I use String[] as HashMap values in Java?
I am a beginner in Java programming. 我是Java编程的初学者。 I want to create a HashMap whose values are String[]'s.
我想创建一个HashMap,其值为String []。
Suppose I have a JTable parametersTable
with values in columns 2, 3, and 4 that I wish to fetch from each row. 假设我有一个
JTable parametersTable
表,希望在每一行中获取第2、3和4列中的值。 Each three-value set constitutes a HashMap
value ( String[]
). 每个三值集构成一个
HashMap
值( String[]
)。
HashMap<String, String[]> map = new HashMap<String, String[]>();
String[] row = {"one", "two", "three", "four", "five", "six", "seven","eight","nine","ten","eleven"};
for (int i=0; i<row.length; i++) {
map.put(row[i], new String[] {
(String) parametersTable.getValueAt(i, 2),
(String) parametersTable.getValueAt(i, 3),
(String) parametersTable.getValueAt(i, 4)});
}
System.out.println(map);
The above code outputs: 上面的代码输出:
{nine=[Ljava.lang.String;@187930f1, six=[Ljava.lang.String;@2a8000ab, four=[Ljava.lang.String;@4436b0fd, one=[Ljava.lang.String;@134bc965, seven=[Ljava.lang.String;@42e49d45, eleven=[Ljava.lang.String;@68cb58ea, ten=[Ljava.lang.String;@198bbc56, two=[Ljava.lang.String;@54464ee3, three=[Ljava.lang.String;@32aeff9b, five=[Ljava.lang.String;@90ed2c, eight=[Ljava.lang.String;@443d9864}
Why is the output something cryptic and not the values like I expect? 为什么输出有些神秘,而不是我期望的值?
Why is the output something cryptic and not the values like I expect?
为什么输出有些神秘,而不是我期望的值?
[Ljava.lang.String;@
is the default representation of String arrays toString() method. [Ljava.lang.String;@
是String数组toString()方法的默认表示。
Use Arrays.toString
method instead. 请改用
Arrays.toString
方法。
So instead of System.out.println(map)
use this to get a meaningful representation 因此,代替
System.out.println(map)
来获取有意义的表示
for(Map.Entry<String, String[]> entry : map.entrySet()) {
System.out.println(entry.getKey() + " -> " + Arrays.toString(entry.getValue()));
}
Try this method :) 试试这个方法:)
static void print(HashMap<String, String[]> map) {
StringBuilder builder = new StringBuilder();
for(Map.Entry<String, String[]> e : map.entrySet()) {
builder.append(e.getKey()).append(" -> [");
boolean tmp = false;
for(String s : e.getValue()) {
if(tmp) {
builder.append(" ");
}
tmp = true;
builder.append(s);
}
builder.append("]\n");
}
System.out.println(builder.toString());
}
You got [Ljava.lang.String;@90ed2c
because default method toString() for array was invoked. 您得到
[Ljava.lang.String;@90ed2c
因为调用了数组的默认方法toString()。
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