java 泛型的使用

来源：互联网发布：sql function函数编辑：程序博客网时间：2024/06/05 00:28

package com.example.hejingzhou.generaldemo;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        Gen<String> gen_1 = new Gen<String>("String");        gen_1.showType();        String str = gen_1.getParameters();        Log.i("MainActivity",str);        gen_1.setParameters("设置完毕");        String str1 = gen_1.getParameters();        Log.i("MainActivity", str1);        Log.i("MainActivity", "----------------------------------------------------");        Gen<Integer> gen_2 = new Gen<Integer>(8888);        gen_2.showType();        int integer = gen_2.getParameters();        Log.i("MainActivity", "" + integer);        gen_2.setParameters(9999);        int int2 = gen_2.getParameters();        Log.i("MainActivity", ""+int2);    }}class Gen<T>{    private T parameters;//定义泛型成员变量    public Gen(T parameters){        this.parameters = parameters;    }    public T getParameters(){        return parameters;    }    public void setParameters(T parameters){        this.parameters = parameters;    }    public void showType(){        Log.i("MainActivity","T的实际类型是"+parameters.getClass());    }}

Log:

04-02 10:49:33.386 9219-9219/com.example.hejingzhou.generaldemo I/MainActivity: T的实际类型是class java.lang.String04-02 10:49:33.386 9219-9219/com.example.hejingzhou.generaldemo I/MainActivity: String04-02 10:49:33.386 9219-9219/com.example.hejingzhou.generaldemo I/MainActivity: 设置完毕04-02 10:49:33.386 9219-9219/com.example.hejingzhou.generaldemo I/MainActivity: ----------------------------------------------------04-02 10:49:33.386 9219-9219/com.example.hejingzhou.generaldemo I/MainActivity: T的实际类型是class java.lang.Integer04-02 10:49:33.386 9219-9219/com.example.hejingzhou.generaldemo I/MainActivity: 888804-02 10:49:33.386 9219-9219/com.example.hejingzhou.generaldemo I/MainActivity: 9999

0 0