我想使用格式创建一个String,用bean中的属性替换格式的一些标记.是否有支持此功能的库或者我是否必须创建自己的实现?
public class Person { private String id; private String name; private String age; //getters and setters }
我希望能够指定类似的格式字符串;
"{name} is {age} years old." "Person id {id} is called {name}."
并使用bean中的值自动填充格式占位符,例如;
String format = "{name} is {age} old." Person p = new Person(1,"Fred","32 years"); String formatted = doFormat(format,person); //returns "Fred is 32 years old."
我看过messageformat,但这似乎只允许我传递数字索引,而不是bean属性.
解决方法
滚动我自己,现在测试.欢迎评论.
import java.lang.reflect.Field; import java.util.regex.Matcher; import java.util.regex.Pattern; public class BeanFormatter<E> { private Matcher matcher; private static final Pattern pattern = Pattern.compile("\\{(.+?)\\}"); public BeanFormatter(String formatString) { this.matcher = pattern.matcher(formatString); } public String format(E bean) throws Exception { StringBuffer buffer = new StringBuffer(); try { matcher.reset(); while (matcher.find()) { String token = matcher.group(1); String value = getProperty(bean,token); matcher.appendReplacement(buffer,value); } matcher.appendTail(buffer); } catch (Exception ex) { throw new Exception("Error formatting bean " + bean.getClass() + " with format " + matcher.pattern().toString(),ex); } return buffer.toString(); } private String getProperty(E bean,String token) throws SecurityException,NoSuchFieldException,IllegalArgumentException,illegalaccessexception { Field field = bean.getClass().getDeclaredField(token); field.setAccessible(true); return String.valueOf(field.get(bean)); } public static void main(String[] args) throws Exception { String format = "{name} is {age} old."; Person p = new Person("Fred","32 years",1); BeanFormatter<Person> bf = new BeanFormatter<Person>(format); String s = bf.format(p); System.out.println(s); } }
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