java 泛型方法 返回泛型结果

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;
}
}