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Java设计模式学习09
Java设计模式学习09
Java设计模式学习09
装饰者模式还是比较难懂的。。。。,我也说不了啥，详解看上面博客,下面案例是我仿照上面博客写的。
-
Behaver 定义行为接口
public interface Behavior { void dressing();//化妆 } -
Person 人类
public class Person implements Behavior { private Behavior behavior; public Person(Behavior behavior) { this.behavior = behavior; } @Override public void dressing() { behavior.dressing(); } } -
Animal 不可否认人也是动物
public class Animal implements Behavior { @Override public void dressing() { System.out.println("化妆。。。"); } } -
男人
public class Man extends Person { public Man(Behavior behavior) { super(behavior); } @Override public void dressing() { super.dressing(); System.out.println("化男人妆。。。"); } } -
女人
public class Woman extends Person { public Woman(Behavior behavior) { super(behavior); } @Override public void dressing() { super.dressing(); System.out.println("化女人妆。。。"); } } -
测试类
/** * 装饰者案例 */ public class Demo { public static void main(String[] args) { System.out.println("=====================动物化妆========================"); Animal animal = new Animal(); animal.dressing(); System.out.println("=====================男人化妆========================"); Man man = new Man(animal); man.dressing(); System.out.println("=====================女人化妆========================"); Woman woman = new Woman(animal); woman.dressing(); System.out.println("=====================人妖化妆========================"); Woman woman1 = new Woman(man); woman1.dressing(); } }
结果
我们可以看到，实例化女人1的时候换了一个实例组合，于是就出现了新的功能。。。
字符输出流使用缓冲----FileReader和BufferedReader
- FileReader 文件字符输入流
- BufferedReader 缓冲字符输入出流
BufferedReaderr缓冲字符输出流，直接继承自Reader
构造方法
public BufferedReader(Reader var1, int var2) {
super(var1);
this.markedChar = -1;
this.readAheadLimit = 0;
this.skipLF = false;
this.markedSkipLF = false;
if(var2 <= 0) {
throw new IllegalArgumentException("Buffer size <= 0");
} else {
this.in = var1;
this.cb = new char[var2];
this.nextChar = this.nChars = 0;
}
}
public BufferedReader(Reader var1) {
this(var1, defaultCharBufferSize);
}
同BufferWriter一样，两个构造方法。实例化的时候需要一个Reader实例。
运用案例
/**
* 读取Demo6.java的内容
*/
public class Demo{
public static final String PATH = "/Volumes/huang/studyfromGitHub/JavaForAndroid/JavaForAndroid/series10/src/main/java/com/example/Demo6.java";
public static void main(String[] args) {
//1.申明
FileReader reader = null;
BufferedReader bufferedReader = null;
try {
//2.实例化
reader = new FileReader(PATH);
bufferedReader = new BufferedReader(reader);
//3.读取
String msg=null;
while ((msg=bufferedReader.readLine())!=null){//如果是null，则表示文件结束
System.out.println(msg);
}
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
bufferedReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
结果
装饰者模式再运用----自定义BufferReader
-
自定义BufferReader类
class CoustomerBufferReader { private Reader in; //缓冲数组 private char[] buffer=new char[1024]; //每次读取的字符个数 private int nChars; //缓冲数组的索引下标 private int nextChar; public CoustomerBufferReader(Reader in) { this.in = in; } public int read() throws IOException { if (nChars == 0) {//表示缓冲中没有可读的字符 //读取节点流（字符流）中数据到缓冲数组中 nChars = in.read(buffer); nextChar = 0; } if (nChars < 0) {//判断是否读取末尾 return -1; } int num = buffer[nextChar++];//从缓冲数组中获取一个字符 nChars--;//读一轮，减一个 return num; } public String readLine() throws IOException { int num = -1; StringBuilder builder = new StringBuilder(); while ((num = read()) != -1) { if (num == '\r') { continue; } else if (num == '\n') { return builder.toString(); } builder.append((char) num);//将读取的一个字符存放到变量中 } //防止最后一行不存在换行符时，无法读取最后一行 if (builder.length() > 0) return builder.toString(); return null; } } -
测试类
public class Demo{ public static void main(String[] args) { try { //读取Demo6中的内容 FileReader reader = new FileReader(Demo7.PATH); //使用自己的CoustomerBufferReader CoustomerBufferReader bufferReader=new CoustomerBufferReader(reader); String line=null; while ((line=bufferReader.readLine())!=null){ System.out.println(line); } } catch (Exception e) { e.printStackTrace(); } } }
结果
缓冲字符输入，输出流复制文件案例
讲道理正长是这样写
public class Demo {
//拷贝源文件
public static final String PATH = "/Volumes/huang/studyfromGitHub/JavaForAndroid/JavaForAndroid/series10/src/main/java/com/example/Demo6.java";
public static final String NAME = "testDemo9.java";
public static void main(String[] args) {
FileReader reader = null;
BufferedReader bufferedReader = null;
FileWriter fileWriter = null;
BufferedWriter bufferedWriter = null;
try {
reader = new FileReader(PATH);
bufferedReader = new BufferedReader(reader);
fileWriter = new FileWriter(Config.PATH + NAME);
bufferedWriter = new BufferedWriter(fileWriter);
String line = null;
while ((line = bufferedReader.readLine()) != null) {
//读一行，写一行
bufferedWriter.write(line);
bufferedWriter.flush();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
bufferedReader.close();
bufferedWriter.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
运行一看结果,傻眼了:
它一行写到死。这可不行，我们看一下，除了没换行，其他都对，那我们控制它换行就可以了。
-
完美版 核心代码替换
boolean isFirstLine=true;//刚开始绝B第一行 while ((line = bufferedReader.readLine()) != null) { //读一行，写一行 if (isFirstLine){//第一行直接写 bufferedWriter.write(line); isFirstLine=false;//写完之后绝B不是第一行了 }else { bufferedWriter.newLine();//插入换行 bufferedWriter.write(line); } bufferedWriter.flush(); } -
运行结果
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