概念

所谓链式，也就是每次调用对象方法后返回的都是该对象本身，而该对象又可以继续调用方法。

例子

public class Demo {
    private String path;
    private Map<String, Object> data;

    public Demo(String path) {
        this.path = path;
        data = new HashMap<String, Object>();
    }

    public Demo data(String key, Object value) {
        data.put(key, value);
        return this;
    }

    public String getPath() {
        return path;
    }

    public Map<String, Object> getData() {
        return data;
    }

    public void setData(Map<String, Object> data) {
        this.data = data;
    }

    public static void main(String[] args) {
        Demo demo = new Demo("12").data("12","12");
        System.out.println(demo.getData());
    }
}