Java_编程实例_需求四

需求：

向list集合添加姓名{张三,李四,王五,二丫,钱六,孙七},将二丫替换为王小丫,写入到"test..txt"

<pre name="code" class="java">//需求四：向list集合添加姓名{张三,李四,王五,二丫,丫蛋,狗剩},将二丫替换为王小丫,写入到"test.txt"public class Test4 {public static void main(String[] args) throws IOException, ClassNotFoundException {// 1.创建List集合对象List<String> list = new ArrayList<>();// 2.存入数据list.add("张三");list.add("李四");list.add("王五");list.add("二丫");list.add("丫蛋");list.add("狗剩");// 3.遍历集合/*// 方式一：迭代器遍历Iterator<String> it = list.iterator();while(it.hasNext()){String thisName = it.next();if("二丫".equals(thisName)){//无法完成操作，此方法不通}}*///方式二：普通for遍历for (int i = 0; i < list.size(); i++) {//获取当前元素String thisName = list.get(i);//判断，替换if("二丫".equals(thisName)){list.set(i, "王小丫");//将当前元素，改为"王小丫"}}System.out.println(list);//4.将List集合写入到"test.txt"（当前项目路径下）//方式一//4.1创建FileWriter对象FileWriter fw = new FileWriter("test.txt");//4.2增强for，写入文件中for(String thisName:list){fw.write(thisName+"\r\n");}//4.3关闭流对象fw.close();//方式二：//4.1创建文件字节输出流对象FileOutputStream fos = new FileOutputStream("test.txt");//4.2遍历数组，将内容写入到文件中for(String thisName:list){fos.write((thisName+"\r\n").getBytes());}//4.3关闭流对象fos.close();FileInputStream fis = new FileInputStream("test.txt");byte[] bytes = new byte[1024];int len=-1;while(-1!=(len= fis.read(bytes))){System.out.println(new String(bytes,0,len));}fis.close();//方式三：//4.1创建对象字节输出流ObjectOutputStream oos = new  ObjectOutputStream(new FileOutputStream("test.txt"));//4.2将list对象写入到文件oos.writeObject(list);oos.close();//4.3创建对象字节输入流ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test.txt"));//4.4从文件中读取对象，并进行强制转换List<String> list2 = (List<String>)ois.readObject();for(String thisName :list2){System.out.println(thisName);}//4.5关闭流ois.close();}}