P573 泛型与File-通配符的使用
@Test
public void test2(){
List
P574 泛型与File-使用通配符后数据的读取和写入要求
ArrayList list3 = new ArrayList<>();
list3.add("AA");
list3.add("BB");
list3.add("CC");
list = list3;
// 添加 对于List就不能向其内部添加数据，只能添加null
// 获取 允许读取数据，读取的数据类型为object
Object o = list.get(0);
System.out.println(o);
P575 泛型与File-有限制条件的通配符的使用
@Test
public void test3(){
List list1 = null;
List list2 = null;
List list3 = null;
List list4 = null;
List
P576 泛型与File-自定义泛型类练习
P577 泛型与File-File类的实例化
package com.io;
import org.junit.Test;
import java.io.File;
public class FileTest {
@Test
public void test1(){
// 构造器1
File file1 = new File("hello.txt"); // 相对于当前module
File file2 = new File("D:\XX\XX"); // 绝对路径
// 构造器2
File file3 = new File("D:\xx","xx");
// 构造器3
File file4 = new File(file3, "A.txt");
}
}
P578 泛型与File-File类的常用方法1
@Test
public void test2(){
File file1 = new File("hello.txt");
File file2 = new File("D:\io\hi.txt");
System.out.println(file1.getAbsoluteFile());
System.out.println(file1.getPath());
System.out.println(file1.getName());
System.out.println(file1.getParent());
System.out.println(file1.length());
System.out.println(new Date(file1.lastModified()));
System.out.println();
System.out.println(file2.getAbsoluteFile());
System.out.println(file2.getPath());
System.out.println(file2.getName());
System.out.println(file2.getParent());
System.out.println(file2.length());
System.out.println(file2.lastModified());
}
@Test
public void test3(){
File file = new File("D:\Java_Program_test\狂神说\JavaSE\基础语法\src\com");
String[] list = file.list();
for (String s : list){
System.out.println(s);
}
File[] files = file.listFiles();
for (File file1 : files) {
System.out.println(file1);
}
}
@Test
public void test4(){
File file1 = new File("D:\Java_Program_test\狂神说\JavaSE\基础语法\hi.txt");
File file2 = new File("hello.txt");
boolean b = file1.renameTo(file2);
System.out.println(b);
}
