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;}}