我们如何在Java 9的JShell中导入gson库？
Java9 引入了名为JShell的交互式REPL命令行工具。它使我们能够执行Java代码段并立即获得结果。我们可以导入可以通过类路径从JShell会话访问的外部类。GSON库是一个Java序列化/反序列化文库用于转化的Java对象转换成JSON ，反之亦然。
在下面的代码片段中，我们可以在JShell中设置类路径
jshell> /env --class-path C:\Users\User\gson.jar | Setting new options and restoring state.
将gson库 导入JShell 之后，便可以在列表中看到该库。
jshell> import com.google.gson.*
jshell> /import
| import java.io.*
| import java.math.*
| import java.net.*
| import java.nio.file.*
| import java.util.*
| import java.util.concurrent.*
| import java.util.function.*
| import java.util.prefs.*
| import java.util.regex.*
| import java.util.stream.*
| import com.google.gson.*
jshell> Gson g = new GsonBuilder().setPrettyPrinting().create()
g ==> {serializeNulls:false,factories:[Factory[typeHier ... 78b9],instanceCreators:{}}在下面的代码片段中，我们创建了一个Employee 类。
jshell> class Employee {
...> private String firstName;
...> private String lastName;
...> private String designation;
...> private String location;
...> public Employee(String firstName, String lastName, String desigation, String location) {
...> this.firstName = firstName;
...> this.lastName = lastName;
...> this.designation = designation;
...> this.location = location;
...> }
...> public String getFirstName() {
...> return firstName;
...> }
...> public String getLastName() {
...> return lastName;
...> }
...> public String getJobDesignation() {
...> return designation;
...> }
...> public String getLocation() {
...> return location;
...> }
...> public String toString() {
...> return "Name = " + firstName + ", " + lastName + " | " +
...> "Job designation = " + designation + " | " +
...> "location = " + location + ".";
...> }
...> }
| created class Employee
jshell> Employee e = new Employee("Jai", "Adithya", "Content Developer", "Hyderabad");
e ==> Name = Jai, Adithya | Job designation = Content D ... er | location = Hyderabad.
jshell> String empSerialized = g.toJson(e)
empSerialized ==> "{\n \"firstName\": \"Jai\",\n \"lastName\": \" ... ation\": \"Hyderabad\"\n}"在下面的代码片段中，我们可以创建一个Employee 对象的实例并显示结果。
jshell> System.out.println(empSerialized)
{
"firstName": "Jai",
"lastName": "Adithya",
"designation": "Content Developer",
"location": "Hyderabad"
}
jshell> Employee e1 = g.fromJson(empSerialized, Employee.class)
e1 ==> Name = Jai, Adithya | Job designation = Content D ... er | location = Hyderabad.