#Java Builder模式-组装复杂的实例。

• 上一面介绍 简单介绍了下我在项目中的使用。

Builder

• 什么是Builder模式？

  • ​ 大都市中林立着许多高楼大厦，这些高楼大厦都是具有建筑结构的大型建筑。通常，建造和构建这种具有建筑结构的大型物体在英文中成为Build。

    ​ 在建筑大楼时，需要打牢地基，搭建框架，然后自下而上地一层一层盖起来。通常，在建造这种具有复杂结构的物体时，很难一气呵成。我们需要首先建造组成这个物体的各个部分，然后分段将他们组装起来。

    ​ ---图解设计模式

• 这个用例并不是特别的明显，大体的思路是这样的。

• 改造上次的代码。首先分析下上篇文章中ztree的数据结构

• 依赖库
  • commons-lang3
    • 3.4
  • com.thoughtworks.xstream
    • 1.4.10
  • com.fasterxml.jackson.core
    • 2.8.1

Builder中角色

关系大概就是这样的样子

• 建造者 Builder
• 具体建造者ConcreteBuilder
  • ZtreeJSONBuilder
  • ZtreeXMLBuilder
• 监工 Director
• 测试 Testing

participant Testingparticipant Directorparticipant ConstructBuilderTesting -> ConstructBuilder: newTesting -> Director : constructDirector -> ConstructBuilder : initConstructBuilder -->> Director : Director-->> Testing: successful

Builder建造者

package cn.z201.gof.builder; import java.util.Collection; public abstract class ZtreeBuilder
    
      { 	public static final String TOP = "0001"; 	 	public abstract String treeName(); 	 	public abstract Object findResuls(); 	 	public abstract void id(String id); 	 	public abstract void pid(String pid); 	 	public abstract void name(String name); 	 	public abstract void url(String url); 	 	public abstract void open(boolean open); 	 	public abstract void parent(boolean parent); 	 	public abstract void children(Collection
     
       children); 	 	public abstract String id(); 	 	public abstract String pid(); 	 	public abstract String name(); 	 	public abstract String url(); 	 	public abstract boolean open(); 	 	public abstract boolean parent(); 	 	public abstract Collection
      
        children(); 	 	 }
      
     
    

ConcreteBuilder具体的建造者

package cn.z201.gof.builder;  import java.util.ArrayList;  import java.util.Collection;  import cn.z201.gof.utils.JsonUtil;  public class ZtreeJSONBuilder extends ZtreeBuilder
    
     {  	      //本级Id      private String id;       //父级菜单的 id      private String pid;       //中文名称      private String name;       //点击地址      private String url;       //是否展开      private boolean open;       //是否为父节点      private boolean isParent;             private Collection
     
       children = new ArrayList
      
       ();;        	public ZtreeJSONBuilder() {  		  	}        	@Override  	public String treeName() {  		return this.getClass().getSimpleName();  	}  	      @Override      public Object findResuls(){      	return JsonUtil.toJson(this);      }  	  	@Override  	public void id(String id) {  		this.id = id;  	}  	@Override  	public void pid(String pid) {  		this.pid = pid;  	}  	@Override  	public void name(String name) {  		this.name = name;  	}  	@Override  	public void url(String url) {  		this.url = url;  	}  	@Override  	public void open(boolean open) {  		this.open = open;  	}  	@Override  	public void parent(boolean isParent) {  		this.isParent = isParent;  	}  	@Override  	public void children(Collection
       
         children) {  		this.children = (Collection
        
         ) children;  	}  	  	@Override  	public String id() {  		return this.id;  	}  	@Override  	public String pid() {  		return this.pid;  	}  	@Override  	public String name() {  		return this.name;  	}  	@Override  	public String url() {  		return this.url;  	}  	@Override  	public boolean open() {  		return this.open;  	}  	@Override  	public boolean parent() {  		return this.isParent;  	}  	@Override  	public Collection
         
           children() { return this.children; } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getPid() { return pid; } public void setPid(String pid) { this.pid = pid; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } public boolean isOpen() { return open; } public void setOpen(boolean open) { this.open = open; } public boolean getIsParent() { return isParent; } public void setIsParent(boolean isParent) { this.isParent = isParent; } public Collection
          
            getChildren() { return children; } public void setChildren(Collection
           
             children) { this.children = children; } } package cn.z201.gof.builder; import java.util.ArrayList; import java.util.Collection; import com.thoughtworks.xstream.XStream; import com.thoughtworks.xstream.annotations.XStreamAlias; import cn.z201.gof.utils.XMLUtil; @XStreamAlias("ZtreeXMLBuilder") public class ZtreeXMLBuilder extends ZtreeBuilder
            
             { //本级Id private String id; //父级菜单的 id private String pid; //中文名称 private String name; //点击地址 private String url; //是否展开 private boolean open; //是否为父节点 private boolean isParent; private Collection
             
               children = new ArrayList
              
               (); public ZtreeXMLBuilder() { } @Override public String treeName() { return this.getClass().getSimpleName(); } @Override public Object findResuls(){ XStream xstream = new XStream(); xstream.autodetectAnnotations(true); xstream.alias("ZtreeXMLBuilder", ZtreeXMLBuilder.class); xstream.registerConverter(new XMLUtil()); return xstream.toXML(this); } @Override public void id(String id) { this.id = id; } @Override public void pid(String pid) { this.pid = pid; } @Override public void name(String name) { this.name = name; } @Override public void url(String url) { this.url = url; } @Override public void open(boolean open) { this.open = open; } @Override public void parent(boolean isParent) { this.isParent = isParent; } @Override public void children(Collection
               
                 children) { this.children = (Collection
                
                 ) children; } @Override public String id() { return this.id; } @Override public String pid() { return this.pid; } @Override public String name() { return this.name; } @Override public String url() { return this.url; } @Override public boolean open() { return this.open; } @Override public boolean parent() { return this.isParent; } @Override public Collection
                 
                   children() { return this.children; } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getPid() { return pid; } public void setPid(String pid) { this.pid = pid; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } public boolean getOpen() { return open; } public void setOpen(boolean open) { this.open = open; } public boolean getIsParent() { return isParent; } public void setIsParent(boolean isParent) { this.isParent = isParent; } public Collection
                  
                    getChildren() { return children; } public void setChildren(Collection
                   
                     children) { this.children = children; } }
                   
                  
                 
                
               
              
             
            
           
          
         
        
       
      
     
    

Director监工

package cn.z201.gof.builder;  import cn.z201.gof.utils.CodingFactoryUtil;  public class Director{  	  	private ZtreeBuilder
     ztreeBuilder;  	  	public 
    
     > Director(ZtreeBuilder
     
       builder){  		ztreeBuilder = builder;  	}  	  	public Object getResuls(){  	    return  ztreeBuilder.findResuls();  	}  	  	public void  construct(){  		if(null == ztreeBuilder.id()){  			ztreeBuilder.id(ZtreeBuilder.TOP);  		}  		  		if(null == ztreeBuilder.name()){  			ztreeBuilder.name(ztreeBuilder.treeName());  		}  		  		if(null == ztreeBuilder.pid()){  			ztreeBuilder.pid(CodingFactoryUtil.ztreeCodingFactory(ZtreeBuilder.TOP, ZtreeBuilder.TOP));  		}else{  			ztreeBuilder.pid(CodingFactoryUtil.ztreeCodingFactory(ztreeBuilder.pid(), ztreeBuilder.id()));  		}  	}  }
     
    

工具类

package cn.z201.gof.utils;import org.apache.commons.lang3.StringUtils;import org.apache.log4j.Logger;public class CodingFactoryUtil {		private static final Logger LOGGER = Logger.getLogger(CodingFactoryUtil.class);		/** ztree的编码加工规则 */	public static final int ztreeRules = 4;		/** 补码 */	public static final String complement = "0";		/**	 * @param head 前置编码 比如0001	 * @param tail 后置编码 比如1	 * @param reules 编码长度 比如4 表示长度四位	 * @return 00010001	 * @throws Exception 	 */	public static String codingFactory(String head ,String tail ,int reules) throws Exception{		if(tail.length() > reules) throw new Exception();		for (int i = 0; i < reules; i++) {			if(tail.length() == reules) break;			tail = StringUtils.join(complement , tail);		}		return StringUtils.join(head , tail);	}		public static String ztreeCodingFactory(String head , String tail){		try {			return codingFactory(head , tail , ztreeRules);		} catch (Exception e) {			LOGGER.error(e.getMessage());		}		return null;	}	}package cn.z201.gof.utils;import com.fasterxml.jackson.annotation.JsonInclude;import com.fasterxml.jackson.core.JsonGenerationException;import com.fasterxml.jackson.core.JsonParseException;import com.fasterxml.jackson.core.type.TypeReference;import com.fasterxml.jackson.databind.DeserializationFeature;import com.fasterxml.jackson.databind.JsonMappingException;import com.fasterxml.jackson.databind.ObjectMapper;import com.fasterxml.jackson.databind.SerializationFeature;import java.io.IOException;import java.text.SimpleDateFormat;import java.util.TimeZone;/** * JSON 和 Java对象相互转换 */public class JsonUtil {    private static final ObjectMapper objectMapper;    static {        objectMapper = new ObjectMapper();        //去掉默认的时间戳格式        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);        //设置为中国上海时区        objectMapper.setTimeZone(TimeZone.getTimeZone("GMT+8"));        objectMapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);        //空值不序列化        objectMapper.setSerializationInclusion(JsonInclude.Include.ALWAYS);        //反序列化时，属性不存在的兼容处理        objectMapper.getDeserializationConfig().withoutFeatures(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);        //序列化时，日期的统一格式        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));        objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);        //单引号处理        objectMapper.configure(com.fasterxml.jackson.core.JsonParser.Feature.ALLOW_SINGLE_QUOTES, true);        objectMapper.configure(com.fasterxml.jackson.core.JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);        //objectMapper.configure(com.fasterxml.jackson.core.JsonParser.Feature.CANONICALIZE_FIELD_NAMES, true);    }    public static 
    
      T toObject(String json, Class
     
       clazz) {        try {            return objectMapper.readValue(json, clazz);        } catch (JsonParseException e) {            throw new MepException(e);        } catch (JsonMappingException e) {            throw new MepException(e);        } catch (IOException e) {            throw new MepException(e);        }    }    public static 
      
        T toCollection(String json, TypeReference
       
         typeReference) {        try {            return objectMapper.readValue(json, typeReference);        } catch (JsonParseException e) {            throw new MepException(e);        } catch (JsonMappingException e) {            throw new MepException(e);        } catch (IOException e) {            throw new MepException(e);        }    }    public static 
        
          String toJson(T entity) {        try {            return objectMapper.writeValueAsString(entity);        } catch (JsonGenerationException e) {            throw new MepException(e);        } catch (JsonMappingException e) {            throw new MepException(e);        } catch (IOException e) {            throw new MepException(e);        }    }}/**   * Copyright © 2017 z201.cn . All rights reserved. * @Title: XMLUtil.java * @Prject: learn-gof * @Package: cn.z201.gof.utils * @author: int_java_se@163.com * @date: 2017年7月15日 上午3:51:36 */package cn.z201.gof.utils;import java.lang.reflect.Field;  import java.lang.reflect.Method;  import java.lang.reflect.ParameterizedType;  import java.lang.reflect.Type;  import java.util.Arrays;  import java.util.Collection;  import java.util.List;  import java.util.Set;    import com.thoughtworks.xstream.converters.Converter;  import com.thoughtworks.xstream.converters.MarshallingContext;  import com.thoughtworks.xstream.converters.UnmarshallingContext;  import com.thoughtworks.xstream.io.HierarchicalStreamReader;  import com.thoughtworks.xstream.io.HierarchicalStreamWriter;  public class XMLUtil  implements Converter{  	 @SuppressWarnings("rawtypes")  	    private Class currentType;  	    private final String clazzNames[] = {"ZtreeXMLBuilder"};// 定义所要转换的对象及所包含的对象名称  	    private List
         
           clazzNamesList; @SuppressWarnings("rawtypes") @Override public boolean canConvert(Class type) { currentType = type; clazzNamesList = Arrays.asList(clazzNames); if (clazzNamesList.contains(currentType.getSimpleName())) { return true; } else { return false; } } @Override public void marshal(Object source, HierarchicalStreamWriter writer, MarshallingContext context) { try { marshalSuper(source, writer, context, currentType); } catch (Exception e) { e.printStackTrace(); } } @SuppressWarnings({ "unchecked", "rawtypes" }) private Object getObj(Class clazz, String nodeName, Object source) throws Exception { Method method = clazz.getMethod("get" + Character .toUpperCase(nodeName.substring(0, 1).toCharArray()[0]) + nodeName.substring(1)); Object obj = null; obj = method.invoke(clazz.cast(source), new Object[0]); return obj; } @SuppressWarnings({ "rawtypes" }) private void objConverter(Object source, HierarchicalStreamWriter writer, MarshallingContext context, Class clazz, String nodeName, Class fieldClazz) throws Exception { Object obj = getObj(clazz, nodeName, source); writer.startNode(nodeName); marshalSuper(obj, writer, context, fieldClazz); writer.endNode(); } @SuppressWarnings({ "rawtypes" }) private void collectionConverter(Object source, HierarchicalStreamWriter writer, MarshallingContext context, Class clazz, String nodeName, Field field) throws Exception { Type types[] = ((ParameterizedType) field.getGenericType()) .getActualTypeArguments(); Object obj = getObj(clazz, nodeName, source); Collection collection = null; if (field.getType().equals(List.class)) { collection = (List) obj; } else if (field.getType().equals(Set.class)) { collection = (Set) obj; } writer.startNode(nodeName); for (Object object : collection) { String clazzName = ((Class) types[0]).getSimpleName(); writer.startNode(Character.toLowerCase(clazzName.substring(0, 1) .toCharArray()[0]) + clazzName.substring(1)); marshalSuper(object, writer, context, (Class) types[0]); writer.endNode(); } writer.endNode(); } @SuppressWarnings({ "rawtypes" }) private void basicTypeConverter(Object source, HierarchicalStreamWriter writer, MarshallingContext context, Class clazz, String nodeName) throws Exception { Object obj = getObj(clazz, nodeName, source); writer.startNode(nodeName); writer.setValue(obj == null ? "" : obj.toString()); writer.endNode(); } @SuppressWarnings({ "rawtypes" }) private void marshalSuper(Object source, HierarchicalStreamWriter writer, MarshallingContext context, Class clazz) throws Exception { Field fields[] = clazz.getDeclaredFields(); for (Field field : fields) { String nodeName = field.getName(); Class fieldClazz = field.getType(); if (clazzNamesList.contains(fieldClazz.getSimpleName())) { objConverter(source, writer, context, clazz, nodeName, fieldClazz); } else if (Arrays.asList(fieldClazz.getInterfaces()).contains( Collection.class)) { collectionConverter(source, writer, context, clazz, nodeName, field); } else { basicTypeConverter(source, writer, context, clazz, nodeName); } } } @Override public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) { return null; } }
         
        
       
      
     
    

测试

package cn.z201.gof;import org.junit.Test;import cn.z201.gof.builder.Director;import cn.z201.gof.builder.ZtreeBuilderXML;import cn.z201.gof.builder.ZtreeBuilderJSON;public class Testing {	@Test	public void test(){		Director director = new Director(new ZtreeJSONBuilder());		director.construct();		System.out.println(director.getResuls());			director = new Director(new ZtreeXMLBuilder());			director.construct();		System.out.println(director.getResuls());			}	}

测试结果

• 这里做了区分，所以使用了两种数据形式展示。

{"id":"0001","pid":"00010001","name":"ZtreeJSONBuilder","url":null,"open":false,"isParent":false,"children":[]}
      
     
      0001
       
     
      00010001
       
     
      ZtreeXMLBuilder
       
       
     
      false
       
     
      false
       
     
      []