怎样在JAVA寫一個含未知類的參數的方法

Question

private String getMainTitle(List<String> bs){
    for(String b:bs){
        if (b.equals("GOOD"){
            return "string";
        }
    }
    
    return null;
}

private String getMainTitle(String b){
    if (b.equals("GOOD"){
        return "string";
    }
    
    return null;
}

public String getTitleFromString(String b){
    return getMainTitle(b);
}

public String getTitleFromList(List<String> bs){    
    return getMainTitle(bs);
}

請問怎样在JAVA寫一個含未知類的參數的方法?

希望寫一個方法能替代getTitleFromString和getTitleFromList , 比如:

public String getTitleFromList(T<?> t){    
    return getMainTitle(t);
}

但我的語法有誤, 請問該怎样改寫?

Answer 1

public String <T> getMainTitle(T obj){
    if(Map.class.isAssignableFrom(obj.getClass())){
        ((Map<?, ?>) data).forEach((k, v) -> {
            if (v.equals("GOOD")) {
                return "string";
            }
          });            
    } else if(Vector.class.isAssignableFrom(obj.getClass())){
        for(String b:bs){
            if (b.equals("GOOD")) {
                return "string";
            }
        }
    } else if ( b.equals("GOOD") ){
        return "string";
    }
    return null;
}

Answer 2

   private String getMainTitle(List<String> bs){
        for(String b:bs){
            if (b.equals("GOOD")) {
                return "string";
            }
        }

        return null;
    }

    private String getMainTitle(String b){
        if (b.equals("GOOD")) {
            return "string";
        }

        return null;
    }

    public String getTitleFrom(String  b){
        return getMainTitle(b);
    }

    public String getTitleFrom(List<String> bs){
        return getMainTitle(bs);
    }

Answer 3

Ça marche

private <T> T getMainTitle(T t){
    if (t.equals("GOOD")){
        return (T)"string";
    }

    return null;
}

public <T> T getTitleFromString(T t){
    return getMainTitle(t);
}

Answer 4

// Object...objs相当一个Object[]数组,用来当做参数，表示有未知个参数传入，甚至可以不传参！
public String getMainTitle(Object...objs) {
    for (Object obj : objs) {
         if(obj.toString().equals("GOOD")){
             return "string";
         }
    }
    return null;
}

// 使用
public void static main(String[] args) {
    getMainTitle();
    getMainTitle("sdfds", "Goods", "GOOD");
    getMainTitle(true, "GOOD");
    getMainTitle(111,1111);
}