在实际的开发中，我们往往需要定义大量的类结构，来实现面向对象式的数据管理。考虑一种场景，这种场景下单个类管理的类成员变量有很多个，我们如何实现在少量代码编写的情况先实现一个类的序列化？
1. 在Java 中要实现一个类的序列化，需要 implements Serializable ，这个类需要是 OPJO 。那么在scala 中，我们知道 BeanProperty 会帮我们实现 get/set 方法，可以极大的缩减代码量
2. 序列化我们使用 alibaba 的fastjson
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.47</version>
<scope>compile</scope>
</dependency>
1. 首先我们看下java 中如何实现：
package java_demo; import java.io.Serializable; public class Students implements Serializable { //姓名 private String name; //年龄 private String age; //住址 private String address; public Students() { } public Students(String name, String age, String address) { this.name = name; this.age = age; this.address = address; } @Override public String toString() { return "Students{" + "name='" + name + ''' + ", age='" + age + ''' + ", address='" + address + ''' + '}'; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getAge() { return age; } public void setAge(String age) { this.age = age; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } }
使用fastjson 序列化：
package java_demo; import com.alibaba.fastjson.JSONObject; public class ToJson { public static void main(String[] args) { System.out.println("---------- Class Students --------"); // object -> json Students s = new Students("wang","10","beijing"); String objStr = JSONObject.toJSONString(s); System.out.println(objStr); // json -> object Students js = JSONObject.parseObject(objStr, Students.class); System.out.println(js); } }
output:
---------- Class Students -------- {"address":"beijing","age":"10","name":"wang"} Students{name='wang', age='10', address='beijing'}
2. 再来看下scala 中如何实现：
1. 手动实现 get/set:
package scala_demo class Students { var name: String = _ var age: String = _ var address: String = _ def this(name: String, age: String, address: String) { this() // 调用主构造函数 this.name = name this.age = age this.address = address } def getName(): String = this.name def getAge(): String = this.age def getAddress(): String = this.address def setName(name: String) = this.name = name def setAge(age: String) = this.age = age def setAddress(address: String) = this.address = address override def toString: String = { this.getClass.getSimpleName + s"{name:'$name',age:'$age',address:'$address'}" } }
2. 使用BeanProperty实现
package scala_demo import scala.beans.BeanProperty class BeanStudents { @BeanProperty var name: String = _ @BeanProperty var age: String = _ @BeanProperty var address: String = _ // 必须实现构造函数 def this(name: String, age: String, address: String) { this() this.name = name this.age = age this.address = address } }
3. 使用case clase + BeanProperty实现
package scala_demo import scala.beans.BeanProperty
case class CaseStudents (
@BeanProperty var name:String="",
@BeanProperty var age:String="",
@BeanProperty var address:String=""
)
序列化：
package scala_demo import com.alibaba.fastjson.JSON import com.alibaba.fastjson.serializer.SerializerFeature object ToJson { def main(args: Array[String]): Unit = { println("--------- Class: Students ---------") // object -> json val students:Students = new Students("Zhao","10","BeiJing") val objStr = JSON.toJSONString(students, SerializerFeature.QuoteFieldNames) println(objStr) val js = JSON.parseObject(objStr,new Students().getClass) println(js) println("--------- Bean Class: Students ---------") val beanStudents = new BeanStudents("Sun","20","HangZhou") val objBeanStr = JSON.toJSONString(beanStudents,SerializerFeature.QuoteFieldNames) println(objBeanStr) val beanJs = JSON.parseObject(objBeanStr,new BeanStudents().getClass) println(beanJs) println(beanJs.name,beanJs.age,beanJs.address) println("--------- Case Class: Students ---------") val caseStudents = CaseStudents("Xian","10","ShangHai") val objCaseStr = JSON.toJSONString(caseStudents ,SerializerFeature.QuoteFieldNames) println(objCaseStr) val caseJs = JSON.parseObject(objCaseStr,CaseStudents().getClass) println(caseJs) } }
output:
--------- Class: Students --------- {"address":"BeiJing","age":"10","name":"Zhao"} Students{name:'Zhao',age:'10',address:'BeiJing'} --------- Bean Class: Students --------- {"address":"HangZhou","age":"20","name":"Sun"} scala_demo.BeanStudents@66480dd7 (Sun,20,HangZhou) --------- Case Class: Students --------- {"address":"ShangHai","age":"10","name":"Xian"} CaseStudents(Xian,10,ShangHai)
可以看到第3中方式可以极大程度的缩减代码量并在此基础上实现序列化
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