如果类的构造器或者静态工厂中具有多个参数，设计这种类时，builder模式就一种不错的选择，特别是当大多数参数都是可选的时候，与使用传统的重叠构造器模式相比，用builder模式的代码更好读和可控。 总结一句话，就是在够着一个对象的时候，需要传入一些参赛，但是有些参数是可以传入的，有些又是可以不用传入的，此时用buide模式就OK了
情景： 现在服务端需要推送一条消息给app端，除了推送的标题，内容不一样以外其余的像什么声音啊，图标啊都一样的，所以在构造的推送内容
的时候就运用buider模式了
public class PushContext {
private String title;
private String body;
private Integer badge;
private String sound;
private String type;
private String action;
private String image;
public static class Builder {
private String title = "title ";
private String body = "body ";
private Integer badge = 1;
private String sound = "default";
private String type = AppProtocolEnum.module.name();
private String action = AppProtocolEnum.module.name();
private String image = "image";
public Builder(String type, Integer bizId) {
this.action = AppProtocolEnum.module.name() + type + "?id=" + bizId;
}
public Builder builderTitle(String title) {
this.title = title;
return this;
}
public Builder builderBody(String body) {
this.body = body;
return this;
}
public Builder builderSound(String sound) {
this.sound = sound;
return this;
}
public Builder builderType(String type) {
this.type = type;
return this;
}
public Builder builderBadge(Integer badge) {
this.badge = badge;
return this;
}
public Builder builderImage(String image){
this.image = image;
return this;
}
public Builder builderAction(String action){
this.action =action;
return this;
}
public PushContext build(){
return new PushContext(this);
}
}
private PushContext(Builder builder) {
this.title = builder.title;
this.body = builder.body;
this.badge = builder.badge;
this.sound = builder.sound;
this.type = builder.type;
this.action = builder.action;
this.image = builder.image;
}
... class buider的 get set 方法...
}
如下运用：
PushContext pushContext = new PushContext.Builder(AppProtocolModuleEnum.bonus.name(),bonusDO.getId()).build();
messagePush.pushMessageToMember(memberId,pushContext);