一分钟教会你使用Builder构建链式调用
使用 构建 调用 一分钟 链式 Builder 教会
2023-06-13 09:15:32 时间
引言
大家好，小面又和大家见面了。相信大家都有可能用到链式调用，比如单元测中的使用：
@Test
public void test() {
// 连续使用多个eq（）的情况
LambdaQueryChainWrapper wrapper1 = PowerMockito.mock(LambdaQueryChainWrapper.class);
LambdaQueryChainWrapper wrapper2 = PowerMockito.mock(LambdaQueryChainWrapper.class);
LambdaQueryChainWrapper wrapper3 = PowerMockito.mock(LambdaQueryChainWrapper.class);
LambdaQueryChainWrapper wrapper4 = PowerMockito.mock(LambdaQueryChainWrapper.class);
LambdaQueryChainWrapper wrapper5 = PowerMockito.mock(LambdaQueryChainWrapper.class);
List list = PowerMockito.mock(ArrayList.class);
PowerMockito.doReturn(wrapper1).when(resourceSubOrderRepository).lambdaQuery();
// eq （）三个参数的情况 ，anyBoolean() 匹配布尔型
PowerMockito.doReturn(wrapper2).when(wrapper1).eq(anyBoolean(), any(), any());
PowerMockito.doReturn(wrapper3).when(wrapper2).eq(anyBoolean(), any(), any());
PowerMockito.doReturn(wrapper4).when(wrapper3).eq(any(), any());
PowerMockito.doReturn(wrapper5).when(wrapper4).eq(any(), any());
PowerMockito.doReturn(list).when(wrapper5).list();
ResponseResult > xx = controller.getInstanceByProductAndRegion(new UserBO(), "00", "xx", "111");
System.out.println(xx.getData());
Assert.assertEquals(new ArrayList<>(), xx.getData());
}
我们可以看到有这种.doXXX.whenXXX.eqXXX这种链式调用法，接下来小面就带你1分钟学会自己写链式调用。
构建对象属性
大家日常在开发创建对象必然都会使用get、set方法。
比如我们创建一个Person类，里面有关于他的多个属性，并写好get、set方法。
public class Person {
private String name;
private Integer age;
private String card;
private Integer mathScore;
private Integer chineseScore;
private Integer chemistryScore;
private Integer physicalScore;
private Integer biologicalScore;
private Integer politicalScore;
private Integer historicalScore;
private Integer geographyScore;
private Integer englishScore;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getCard() {
return card;
}
public void setCard(String card) {
this.card = card;
}
public Integer getMathScore() {
return mathScore;
}
public void setMathScore(Integer mathScore) {
this.mathScore = mathScore;
}
public Integer getChineseScore() {
return chineseScore;
}
public void setChineseScore(Integer chineseScore) {
this.chineseScore = chineseScore;
}
public Integer getChemistryScore() {
return chemistryScore;
}
public void setChemistryScore(Integer chemistryScore) {
this.chemistryScore = chemistryScore;
}
public Integer getPhysicalScore() {
return physicalScore;
}
public void setPhysicalScore(Integer physicalScore) {
this.physicalScore = physicalScore;
}
public Integer getBiologicalScore() {
return biologicalScore;
}
public void setBiologicalScore(Integer biologicalScore) {
this.biologicalScore = biologicalScore;
}
public Integer getPoliticalScore() {
return politicalScore;
}
public void setPoliticalScore(Integer politicalScore) {
this.politicalScore = politicalScore;
}
public Integer getHistoricalScore() {
return historicalScore;
}
public void setHistoricalScore(Integer historicalScore) {
this.historicalScore = historicalScore;
}
public Integer getGeographyScore() {
return geographyScore;
}
public void setGeographyScore(Integer geographyScore) {
this.geographyScore = geographyScore;
}
public Integer getEnglishScore() {
return englishScore;
}
public void setEnglishScore(Integer englishScore) {
this.englishScore = englishScore;
}
@Override
public String toString() {
return "Person{" +
"name='" + name + '\'' +
", age=" + age +
", card='" + card + '\'' +
", mathScore=" + mathScore +
", chineseScore=" + chineseScore +
", chemistryScore=" + chemistryScore +
", physicalScore=" + physicalScore +
", biologicalScore=" + biologicalScore +
", politicalScore=" + politicalScore +
", historicalScore=" + historicalScore +
", geographyScore=" + geographyScore +
", englishScore=" + englishScore +
'}';
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Person person = (Person) o;
return Objects.equals(name, person.name) && Objects.equals(age, person.age) && Objects.equals(card, person.card) && Objects.equals(mathScore, person.mathScore) && Objects.equals(chineseScore, person.chineseScore) && Objects.equals(chemistryScore, person.chemistryScore) && Objects.equals(physicalScore, person.physicalScore) && Objects.equals(biologicalScore, person.biologicalScore) && Objects.equals(politicalScore, person.politicalScore) && Objects.equals(historicalScore, person.historicalScore) && Objects.equals(geographyScore, person.geographyScore) && Objects.equals(englishScore, person.englishScore);
}
@Override
public int hashCode() {
return Objects.hash(name, age, card, mathScore, chineseScore, chemistryScore, physicalScore, biologicalScore, politicalScore, historicalScore, geographyScore, englishScore);
}
}
我们在给它设置属性时，使用set方法
public static void main(String[] args) {
Person person = new Person();
person.setAge(15);
person.setCard("12345");
person.setBiologicalScore(50);
person.setChemistryScore(20);
person.setChineseScore(100);
person.setGeographyScore(80);
person.setHistoricalScore(90);
person.setEnglishScore(10);
person.setMathScore(99);
}
有多少个属性，我们就得手写多少次对吧，如果属性的数量比较多，那么就会写很多，有没有一种舒服点的姿势呢？
lombok的链式调用
那就是链式调用，我们先来直接使用lombok提供的方式。
首先还是创建Person类，添加lombok相关注解
@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class Person2 {
private String name;
private Integer age;
private String card;
private Integer mathScore;
private Integer chineseScore;
private Integer chemistryScore;
private Integer physicalScore;
private Integer biologicalScore;
private Integer politicalScore;
private Integer historicalScore;
private Integer geographyScore;
private Integer englishScore;
}
创建对象赋予属性
public static void main(String[] args) {
//链式调用
Person2.Person2Builder builder = Person2.builder();
Person2 p2 = builder.age(15)
.englishScore(100)
.biologicalScore(100)
.card("12345")
.geographyScore(100)
.historicalScore(100)
.chineseScore(100)
.build();
Integer age = p2.getAge();
}
我们可以看到效果就是在直观视觉上看起来它的属性更规整，并且是一条链式语句，使用起来就更方便。
public static void main(String[] args) {
Person person = new Person();
person.setAge(15);
person.setCard("12345");
person.setBiologicalScore(50);
person.setChemistryScore(20);
person.setChineseScore(100);
person.setGeographyScore(80);
person.setHistoricalScore(90);
person.setEnglishScore(10);
person.setMathScore(99);
//链式调用
Person2.Person2Builder builder = Person2.builder();
Person2 p2 = builder.age(15)
.englishScore(100)
.biologicalScore(100)
.card("12345")
.geographyScore(100)
.historicalScore(100)
.chineseScore(100)
.build();
Integer age = p2.getAge();
}
两种使用方式的的对比显而易见，lombok是靠这个@Builder注解实现对应链式调用，接下来下面也就这个builder实现一下。
自己手动实现链式调用
首先还是创建Person类，添加set、get方法，增加有参无参构造方法
public class Person3 {
private String name;
private Integer age;
private String card;
private Integer mathScore;
private Integer chineseScore;
private Integer chemistryScore;
private Integer physicalScore;
private Integer biologicalScore;
private Integer politicalScore;
private Integer historicalScore;
private Integer geographyScore;
private Integer englishScore;
public Person3() {
}
public Person3(String name, Integer age, String card, Integer mathScore, Integer chineseScore, Integer chemistryScore, Integer physicalScore, Integer biologicalScore, Integer politicalScore, Integer historicalScore, Integer geographyScore, Integer englishScore) {
this.name = name;
this.age = age;
this.card = card;
this.mathScore = mathScore;
this.chineseScore = chineseScore;
this.chemistryScore = chemistryScore;
this.physicalScore = physicalScore;
this.biologicalScore = biologicalScore;
this.politicalScore = politicalScore;
this.historicalScore = historicalScore;
this.geographyScore = geographyScore;
this.englishScore = englishScore;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getCard() {
return card;
}
public void setCard(String card) {
this.card = card;
}
public Integer getMathScore() {
return mathScore;
}
public void setMathScore(Integer mathScore) {
this.mathScore = mathScore;
}
public Integer getChineseScore() {
return chineseScore;
}
public void setChineseScore(Integer chineseScore) {
this.chineseScore = chineseScore;
}
public Integer getChemistryScore() {
return chemistryScore;
}
public void setChemistryScore(Integer chemistryScore) {
this.chemistryScore = chemistryScore;
}
public Integer getPhysicalScore() {
return physicalScore;
}
public void setPhysicalScore(Integer physicalScore) {
this.physicalScore = physicalScore;
}
public Integer getBiologicalScore() {
return biologicalScore;
}
public void setBiologicalScore(Integer biologicalScore) {
this.biologicalScore = biologicalScore;
}
public Integer getPoliticalScore() {
return politicalScore;
}
public void setPoliticalScore(Integer politicalScore) {
this.politicalScore = politicalScore;
}
public Integer getHistoricalScore() {
return historicalScore;
}
public void setHistoricalScore(Integer historicalScore) {
this.historicalScore = historicalScore;
}
public Integer getGeographyScore() {
return geographyScore;
}
public void setGeographyScore(Integer geographyScore) {
this.geographyScore = geographyScore;
}
public Integer getEnglishScore() {
return englishScore;
}
public void setEnglishScore(Integer englishScore) {
this.englishScore = englishScore;
}
@Override
public String toString() {
return "Person{" +
"name='" + name + '\'' +
", age=" + age +
", card='" + card + '\'' +
", mathScore=" + mathScore +
", chineseScore=" + chineseScore +
", chemistryScore=" + chemistryScore +
", physicalScore=" + physicalScore +
", biologicalScore=" + biologicalScore +
", politicalScore=" + politicalScore +
", historicalScore=" + historicalScore +
", geographyScore=" + geographyScore +
", englishScore=" + englishScore +
'}';
}
}
接着在Person3中添加一个静态内部类Builder，添加上Person3中的所有属性
public static class Builder{
private String name;
private Integer age;
private String card;
private Integer mathScore;
private Integer chineseScore;
private Integer chemistryScore;
private Integer physicalScore;
private Integer biologicalScore;
private Integer politicalScore;
private Integer historicalScore;
private Integer geographyScore;
private Integer englishScore;
}
然后创建一个方法，方法名就是属性字段名如name，添加对应参数String name，赋值name，返回Builder自身
public Builder name(String name){
this.name = name;
return this;
}
其他属性也都如此
public static class Builder{
private String name;
private Integer age;
private String card;
private Integer mathScore;
private Integer chineseScore;
private Integer chemistryScore;
private Integer physicalScore;
private Integer biologicalScore;
private Integer politicalScore;
private Integer historicalScore;
private Integer geographyScore;
private Integer englishScore;
public Builder name(String name){
this.name = name;
return this;
}
public Builder age(Integer age){
this.age = age;
return this;
}
public Builder card(String card){
this.card = card;
return this;
}
public Builder mathScore(Integer mathScore){
this.mathScore = mathScore;
return this;
}
public Builder chineseScore(Integer chineseScore){
this.chineseScore = chineseScore;
return this;
}
public Builder chemistryScore(Integer chemistryScore){
this.chemistryScore = chemistryScore;
return this;
}
public Builder physicalScore(Integer physicalScore){
this.physicalScore = physicalScore;
return this;
}
public Builder biologicalScore(Integer biologicalScore){
this.biologicalScore = biologicalScore;
return this;
}
public Builder politicalScore(Integer politicalScore){
this.politicalScore = politicalScore;
return this;
}
public Builder historicalScore(Integer historicalScore){
this.historicalScore = historicalScore;
return this;
}
public Builder geographyScore(Integer geographyScore){
this.geographyScore = geographyScore;
return this;
}
public Builder englishScore(Integer englishScore){
this.englishScore = englishScore;
return this;
}
}
创建build()方法返回Person3
public Person3 build(){
return new Person3(this.name,this.age,this.card,this.mathScore,this.chineseScore,this.chemistryScore,this.physicalScore,this.biologicalScore,this.politicalScore,this.historicalScore,this.geographyScore,this.englishScore);
}
这个时候已经构建完成了
public class Person3 {
private String name;
private Integer age;
private String card;
private Integer mathScore;
private Integer chineseScore;
private Integer chemistryScore;
private Integer physicalScore;
private Integer biologicalScore;
private Integer politicalScore;
private Integer historicalScore;
private Integer geographyScore;
private Integer englishScore;
public Person3() {
}
public Person3(String name, Integer age, String card, Integer mathScore, Integer chineseScore, Integer chemistryScore, Integer physicalScore, Integer biologicalScore, Integer politicalScore, Integer historicalScore, Integer geographyScore, Integer englishScore) {
this.name = name;
this.age = age;
this.card = card;
this.mathScore = mathScore;
this.chineseScore = chineseScore;
this.chemistryScore = chemistryScore;
this.physicalScore = physicalScore;
this.biologicalScore = biologicalScore;
this.politicalScore = politicalScore;
this.historicalScore = historicalScore;
this.geographyScore = geographyScore;
this.englishScore = englishScore;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getCard() {
return card;
}
public void setCard(String card) {
this.card = card;
}
public Integer getMathScore() {
return mathScore;
}
public void setMathScore(Integer mathScore) {
this.mathScore = mathScore;
}
public Integer getChineseScore() {
return chineseScore;
}
public void setChineseScore(Integer chineseScore) {
this.chineseScore = chineseScore;
}
public Integer getChemistryScore() {
return chemistryScore;
}
public void setChemistryScore(Integer chemistryScore) {
this.chemistryScore = chemistryScore;
}
public Integer getPhysicalScore() {
return physicalScore;
}
public void setPhysicalScore(Integer physicalScore) {
this.physicalScore = physicalScore;
}
public Integer getBiologicalScore() {
return biologicalScore;
}
public void setBiologicalScore(Integer biologicalScore) {
this.biologicalScore = biologicalScore;
}
public Integer getPoliticalScore() {
return politicalScore;
}
public void setPoliticalScore(Integer politicalScore) {
this.politicalScore = politicalScore;
}
public Integer getHistoricalScore() {
return historicalScore;
}
public void setHistoricalScore(Integer historicalScore) {
this.historicalScore = historicalScore;
}
public Integer getGeographyScore() {
return geographyScore;
}
public void setGeographyScore(Integer geographyScore) {
this.geographyScore = geographyScore;
}
public Integer getEnglishScore() {
return englishScore;
}
public void setEnglishScore(Integer englishScore) {
this.englishScore = englishScore;
}
@Override
public String toString() {
return "Person{" +
"name='" + name + '\'' +
", age=" + age +
", card='" + card + '\'' +
", mathScore=" + mathScore +
", chineseScore=" + chineseScore +
", chemistryScore=" + chemistryScore +
", physicalScore=" + physicalScore +
", biologicalScore=" + biologicalScore +
", politicalScore=" + politicalScore +
", historicalScore=" + historicalScore +
", geographyScore=" + geographyScore +
", englishScore=" + englishScore +
'}';
}
public static class Builder{
private String name;
private Integer age;
private String card;
private Integer mathScore;
private Integer chineseScore;
private Integer chemistryScore;
private Integer physicalScore;
private Integer biologicalScore;
private Integer politicalScore;
private Integer historicalScore;
private Integer geographyScore;
private Integer englishScore;
public Builder name(String name){
this.name = name;
return this;
}
public Builder age(Integer age){
this.age = age;
return this;
}
public Builder card(String card){
this.card = card;
return this;
}
public Builder mathScore(Integer mathScore){
this.mathScore = mathScore;
return this;
}
public Builder chineseScore(Integer chineseScore){
this.chineseScore = chineseScore;
return this;
}
public Builder chemistryScore(Integer chemistryScore){
this.chemistryScore = chemistryScore;
return this;
}
public Builder physicalScore(Integer physicalScore){
this.physicalScore = physicalScore;
return this;
}
public Builder biologicalScore(Integer biologicalScore){
this.biologicalScore = biologicalScore;
return this;
}
public Builder politicalScore(Integer politicalScore){
this.politicalScore = politicalScore;
return this;
}
public Builder historicalScore(Integer historicalScore){
this.historicalScore = historicalScore;
return this;
}
public Builder geographyScore(Integer geographyScore){
this.geographyScore = geographyScore;
return this;
}
public Builder englishScore(Integer englishScore){
this.englishScore = englishScore;
return this;
}
public Person3 build(){
return new Person3(this.name,this.age,this.card,this.mathScore,this.chineseScore,this.chemistryScore,this.physicalScore,this.biologicalScore,this.politicalScore,this.historicalScore,this.geographyScore,this.englishScore);
}
}
}
直接使用
public static void main(String[] args) {
//自己实现builder
Person3 p3 = new Person3.Builder()
.age(18)
.card("12345")
.mathScore(100)
.chemistryScore(100)
.biologicalScore(100)
.build();
Integer p3Age = p3.getAge();
}
可以看到效果和lombok实现的方式一样，我们自己也可以链式调用自己的对象了。
总结
小面今天的教学到这就结束啦，相信你已经学会了自己如何构建链式调用的方法，后面代码实操可以用起来，能在工作中对你有所帮助的。
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