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。