如何在 Java 9 的 JShell 中匯入 Gson 庫?\n
Java 9 推出了一款名為JShell的互動式REPL命令列工具。它允許我們執行 Java 程式碼段並獲得直接的結果。我們可以匯入可透過類路徑從 JShell 會話訪問的外部類。Gson 庫是一個 Java 序列化/反序列化庫,旨在將Java 物件轉換為JSON 以及反之亦然。
在以下程式碼段中,我們可以在 JShell 中設定類路徑
jshell> /env --class-path C:\Users\User\gson.jar | Setting new options and restoring state.
一旦在 JShell 中匯入了gson 庫 ,就能夠在列表中看到該庫。
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:{}}在以下程式碼段中,我們建立了一個Employee 類。
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}"在以下程式碼段中,我們可以建立Employee 物件的例項並顯示結果。
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.
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