java 泛型方法返回泛型结果

今天药忘吃喽~ 2022-02-28 15:16 313阅读 0赞

[https://blog.csdn.net/dekiven1/article/details/53928739][https_blog.csdn.net_dekiven1_article_details_53928739]

package testDouble;  
  
import java.util.HashMap;  
  
public class Test \{  
static HashMap<String, String> sMap = new HashMap<String, String>();  
public static void main(String\[\] args) \{  
  
sMap.put("1", "23");  
sMap.put("2", "ad");  
sMap.put("3", "1.0");  
sMap.put("4", "false");  
int i = getUserInfoByKey("1", Integer.class, 1);  
String s = getUserInfoByKey("2", String.class, "null");  
float f = getUserInfoByKey("3", Float.class, -0.1f);  
boolean b = getUserInfoByKey("4", Boolean.class, true);  
System.out.println("i:"+i);  
System.out.println("s:"+s);  
System.out.println("f:"+f);  
System.out.println("b:"+b);  
\}  
  
protected static <T> T getUserInfoByKey(String key, Class<T> clazz, T deffault) \{  
T ret = null;  
String v = sMap.get(key);  
if (deffault instanceof Integer) \{  
ret = (clazz.cast(Integer.parseInt(v)));  
\} else if (deffault instanceof String) \{  
ret = clazz.cast(v);  
\} else if (deffault instanceof Double) \{  
ret = clazz.cast(Double.parseDouble(v));  
\} else if (deffault instanceof Float) \{  
ret = clazz.cast(Float.parseFloat(v));  
\} else if (deffault instanceof Long) \{  
ret = clazz.cast(Long.parseLong(v));  
\} else if (deffault instanceof Boolean) \{  
ret = clazz.cast(Boolean.parseBoolean(v));  
\}  
if (null != ret) \{  
return ret;  
\}  
return deffault;  
\}  
\}

[https_blog.csdn.net_dekiven1_article_details_53928739]: https://blog.csdn.net/dekiven1/article/details/53928739