（我是初学者）
我想编译并运行一个名为HelloWorld.java的文件。我安装了最新的jdk，并通过cmd编译了文件。此方法有效，并创建了HelloWorld.class文件。当我尝试命令“ java HelloWorld”时，它说："C:\ProgramData\Oracle\Java\javapath\java.exe"找不到。当我进入该目录时，可以看到java.exe文件。我还为Java\jdk-11.0.1\bin目录设置了路径变量，但是没有任何作用。
为什么总是说找不到文件？
提到的两个目录都有一个java.exe文件。
答案 0 :(得分：2)
我知道了：
安装jdk时，将创建以下路径变量：package com.app.clupascu.oavm;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
public class MainPage extends AppCompatActivity {
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_home:
setTitle("Map");
FirstFragment fragment = new FirstFragment();
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fram, fragment);
fragmentTransaction.commit();
return true;
case R.id.navigation_dashboard:
setTitle("History");
SecondFragment fragment2 = new SecondFragment();
FragmentTransaction fragmentTransaction2 = getSupportFragmentManager().beginTransaction();
fragmentTransaction2.replace(R.id.fram, fragment2);
fragmentTransaction2.commit();
return true;
case R.id.navigation_notifications:
setTitle("Schedule");
ThirdFragment fragment3 = new ThirdFragment();
FragmentTransaction fragmentTransaction3 = getSupportFragmentManager().beginTransaction();
fragmentTransaction3.replace(R.id.fram, fragment3);
fragmentTransaction3.commit();
return true;
}
return false;
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_page);
BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
setTitle("Map");
FirstFragment fragment = new FirstFragment();
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fram, fragment);
fragmentTransaction.commit();
}
}
我删除了它并添加了这个：C:\ProgramData\Oracle\Java\javapath
之后，编译和执行我的文件均按预期工作。
另请参阅：Helpful link