图解设计模式Builder模式
2017-01-18 本文已影响35人
MWY
UML
Paste_Image.png
Builder
//建造者
public abstract class Builder {
public abstract void makeTitle(String title);
public abstract void makString(String str);
public abstract void makeItem(String[] items);
public abstract void close();
}
HTMLBuilder
//具体的建造者
public class HTMLBuilder extends Builder {
private String filename;
private PrintWriter writer;
@Override
public void makeTitle(String title) {
filename = title + ".html";
try {
writer = new PrintWriter(new FileWriter(filename));
} catch (IOException e) {
e.printStackTrace();
}
writer.println("<html><head><title>" + title + "</title></head><body>");
writer.println("<h1>" + title +"</h1>");
}
@Override
public void makString(String str) {
writer.println("<p>" + str + "</p>");
}
@Override
public void makeItem(String[] items) {
writer.println("<ul>");
for (int i = 0; i < items.length; i++) {
writer.println("<li>" + items[i] + "</li>");
}
writer.println("</ul>");
}
@Override
public void close() {
writer.println("</body></html>");
}
public String getResult() {
return filename;
}
}
TextBuilder
//具体的建造者
public class TextBuilder extends Builder {
private StringBuffer buffer = new StringBuffer();
@Override
public void makeTitle(String title) {
buffer.append("=============================\n");
buffer.append("¥" + title + "¥\n");
buffer.append("\n");
}
@Override
public void makString(String str) {
buffer.append("@@" + str + "\n");
buffer.append("\n");
}
@Override
public void makeItem(String[] items) {
for (int i = 0; i < items.length; i++) {
buffer.append(" ." + items[i] + "\n");
}
buffer.append("\n");
}
@Override
public void close() {
buffer.append("=======================\n");
}
public String getResult() {
return buffer.toString();
}
}
Director
//Director使用Builder角色的接口生成实例
public class Director {
private Builder builder;
public Director (Builder builder) {
this.builder = builder;
}
public void construct() {
builder.makeTitle("Greeting");
builder.makString("从早上至下午");
builder.makeItem(new String[] {
"早上好",
"下午好"
});
builder.makString("晚上");
builder.makeItem(new String[]{
"晚上好。",
"晚安。",
"再见。"
});
builder.close();
}
}
Main
public class Main {
public static void main(String[] args) {
// write your code here
TextBuilder textBuilder = new TextBuilder();
Director director = new Director(textBuilder);
director.construct();
String result = textBuilder.getResult();
System.out.println(result);
HTMLBuilder htmlBuilder = new HTMLBuilder();
Director director1 = new Director(htmlBuilder);
director1.construct();
String filename = htmlBuilder.getResult();
System.out.println(filename + "文件编写完成。");
}
}
