Java中Builder模式构建MAP/LIST的具体介绍

下面小编就为大家带来一篇java builder模式构建map/list的实例讲解。小编觉得挺不错的，现在就分享给大家，也给大家做个参考。一起跟随小编过来看看吧

我们在构建一个MAP时，要不停的调用put，有时候看着觉得很麻烦，刚好，看了下builder模式，觉得这思路不错，于是乎，照着用builder模式写了一个构建MAP的示例，

代码如下：

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import java.util.HashMap;
import java.util.Map;
 
public class MapBuilder {
  
 public Builder b;
  
 public MapBuilder(Builder b){
  this.b = b;
 }
  
 public Map map(){
  return b.map;
 }
  
 public T get(String key){
  return b.map.get(key);
 }
 
 public static class Builder{
   
  public Map map;
   
  public Builder(){
   map = new HashMap();
  }
   
  public Builder map(String key, T value){
   map.put(key, value);
   return this;
  }
   
   
  public MapBuilder build(){
   return new MapBuilder(this);
  }
 }
  
 public static void main(String[] args) {
  MapBuilder build = new MapBuilder.Builder().map("a", "b").build();
  System.out.println(build.get("a"));
 }
  
}

public class ListBuilder {
  
 public Builder b;
  
 public ListBuilder(Builder b){
  this.b = b;
 }
  
 public List list(){
  return b.list;
 }
  
 public T get(int index){
  return b.list.get(index);
 }
 
 public static class Builder{
   
  public List list;
   
  public Builder(){
   list = new ArrayList();
  }
  public Builder add(T value){
   list.add(value);
   return this;
  }
  public ListBuilder build(){
   return new ListBuilder(this);
  }
 }
  
 public static void main(String[] args) {
  ListBuilder build = new ListBuilder.Builder().add("a").add("b").build();
  System.out.println(build.get(0));
 }
}