Java从网络取得文件，输入url文件地址，可以得到文件，实例化地址输入框和按钮，实例化一个面板,用于容纳地址输入框和取文件按钮，增加组件到容器上，打开和创建文件输入流并关闭输入流，设置窗口尺寸和可视化，关闭窗口时退出程序。-Java to obtain the files from the network, enter the url file address, you can get the file, instantiated the address input box and button, instantiate a panel for receiving the address input box and take the File button to add the component to the container, open and create files input stream and close the input stream, set the window size and visualization, close the window to exit the program.