在Python中,格式化字符串时,我可以按名称而不是按位置填充占位符,如下所示:
print "There's an incorrect value '%(value)s' in column # %(column)d" % \
{ 'value': x, 'column': y }
我想知道这在Java中是否可能(希望没有外部库)?
在Python中,格式化字符串时,我可以按名称而不是按位置填充占位符,如下所示:
print "There's an incorrect value '%(value)s' in column # %(column)d" % \
{ 'value': x, 'column': y }
我想知道这在Java中是否可能(希望没有外部库)?
当前回答
我试了一下
public static void main(String[] args)
{
String rowString = "replace the value ${var1} with ${var2}";
Map<String,String> mappedValues = new HashMap<>();
mappedValues.put("var1", "Value 1");
mappedValues.put("var2", "Value 2");
System.out.println(replaceOccurence(rowString, mappedValues));
}
private static String replaceOccurence(String baseStr ,Map<String,String> mappedValues)
{
for(String key :mappedValues.keySet())
{
baseStr = baseStr.replace("${"+key+"}", mappedValues.get(key));
}
return baseStr;
}
其他回答
你可以使用StringTemplate库,它提供了你想要的和更多。
import org.antlr.stringtemplate.*;
final StringTemplate hello = new StringTemplate("Hello, $name$");
hello.setAttribute("name", "World");
System.out.println(hello.toString());
这是一个旧的线程,但只是为了记录,你也可以使用Java 8风格,像这样:
public static String replaceParams(Map<String, String> hashMap, String template) {
return hashMap.entrySet().stream().reduce(template, (s, e) -> s.replace("%(" + e.getKey() + ")", e.getValue()),
(s, s2) -> s);
}
用法:
public static void main(String[] args) {
final HashMap<String, String> hashMap = new HashMap<String, String>() {
{
put("foo", "foo1");
put("bar", "bar1");
put("car", "BMW");
put("truck", "MAN");
}
};
String res = replaceParams(hashMap, "This is '%(foo)' and '%(foo)', but also '%(bar)' '%(bar)' indeed.");
System.out.println(res);
System.out.println(replaceParams(hashMap, "This is '%(car)' and '%(foo)', but also '%(bar)' '%(bar)' indeed."));
System.out.println(replaceParams(hashMap, "This is '%(car)' and '%(truck)', but also '%(foo)' '%(bar)' + '%(truck)' indeed."));
}
输出将是:
This is 'foo1' and 'foo1', but also 'bar1' 'bar1' indeed.
This is 'BMW' and 'foo1', but also 'bar1' 'bar1' indeed.
This is 'BMW' and 'MAN', but also 'foo1' 'bar1' + 'MAN' indeed.
我试了一下
public static void main(String[] args)
{
String rowString = "replace the value ${var1} with ${var2}";
Map<String,String> mappedValues = new HashMap<>();
mappedValues.put("var1", "Value 1");
mappedValues.put("var2", "Value 2");
System.out.println(replaceOccurence(rowString, mappedValues));
}
private static String replaceOccurence(String baseStr ,Map<String,String> mappedValues)
{
for(String key :mappedValues.keySet())
{
baseStr = baseStr.replace("${"+key+"}", mappedValues.get(key));
}
return baseStr;
}
不幸的是,答案是否定的。然而,你可以非常接近一个合理的语法:
"""
You are $compliment!
"""
.replace('$compliment', 'awesome');
它比String更具可读性和可预测性。至少是格式!
Apache Commons Lang的replaceEach方法可能会根据您的特定需求派上用场。你可以简单地用这个方法调用来替换占位符:
StringUtils.replaceEach("There's an incorrect value '%(value)' in column # %(column)",
new String[] { "%(value)", "%(column)" }, new String[] { x, y });
给定一些输入文本,这将用第二个字符串数组中的相应值替换第一个字符串数组中出现的所有占位符。