在使用jQuery时候，我们经常会看到或者使用到方法链，例如：

$("#p1").css("color","red").slideUp(2000).slideDown(2000);

这段代码的意思是选择器选择id为p1的html标签，颜色变红，之后slideup，再slidedown。

自然是可以将这几个方法分开写，但是不分开的话不仅有很好的易读性，代码量也会有减少，那么何乐而不为？这种调用函数的方式在jQuery中称为“Chaining”，原理也很简单：能够chaining的方法调用后返回对象本身即可。

下面用java代码做个演示：

Person.java

 public class Persion { private int id; private String name; private String phoneNumber; private String address; public Persion() { } public void setId(int id) {  this.id = id; } public void setName(String name) { this.name = name; } public void setPhoneNumber(String phoneNumber) { this.phoneNumber = phoneNumber; } public void setAddress(String address) { this.address = address; } public void printId() { System.out.println(this.id); } public void printName() { System.out.println(this.name); } public void printPhoneNumber() { System.out.println(this.phoneNumber); } public void printAddress() { System.out.println(this.address); }}

Test.java

public class Test { public static void main(String[] args) { Persion persion1 = new Persion(); persion1.setId(3); persion1.setName("John"); persion1.setPhoneNumber("1111111"); persion1.setAddress("US"); persion1.printId(); persion1.printName();  persion1.printPhoneNumber(); persion1.printAddress(); }}

使用chaining：

Person.java

 public class Persion { private int id; private String name; private String phoneNumber; private String address; public Persion() { } public Persion setId(int id) {  this.id = id; return this; } public Persion setName(String name) { this.name = name; return this; } public Persion setPhoneNumber(String phoneNumber) { this.phoneNumber = phoneNumber; return this; } public Persion setAddress(String address) { this.address = address; return this; } public Persion printId() { System.out.println(this.id); return this; } public Persion printName() { System.out.println(this.name); return this; } public Persion printPhoneNumber() { System.out.println(this.phoneNumber); return this; } public Persion printAddress() { System.out.println(this.address); return this; }}

Test.java：

public class Test {

public static void main(String[] args) {

Persion persion1 = new Persion();

persion1.setId(3).setName("John")

.setPhoneNumber("1111111").setAddress("US");

persion1.printId()

.printName()

.printPhoneNumber()

.printAddress();

}

}

链式方法，就是在除最后一个方法外，每个方法都返回一个对象或者调用同一个对象的多个方法。这种编程方式：编程性强；可读性强；代码简洁。但是不易于调试。