再進(jìn)入學(xué)習(xí)jackson庫(kù)的細(xì)節(jié)之前,讓我們來(lái)看看應(yīng)用程序操作功能。在這個(gè)例子中,我們創(chuàng)建一個(gè)Student類。將創(chuàng)建一個(gè)JSON字符串學(xué)生的詳細(xì)信息,并將其反序列化到學(xué)生的對(duì)象,然后將其序列化到JSON字符串。
創(chuàng)建一個(gè)名為JacksonTester在Java類文件 C:\>Jackson_WORKSPACE.
文件: JacksonTester.java
import java.io.IOException; import org.codehaus.jackson.JsonParseException; import org.codehaus.jackson.map.JsonMappingException; import org.codehaus.jackson.map.ObjectMapper; import org.codehaus.jackson.map.SerializationConfig; public class JacksonTester { public static void main(String args[]){ ObjectMapper mapper = new ObjectMapper(); String jsonString = "{\"name\":\"Mahesh\", \"age\":21}"; //map json to student try { Student student = mapper.readValue(jsonString, Student.class); System.out.println(student); mapper.enable(SerializationConfig.Feature.INDENT_OUTPUT); jsonString = mapper.writeValueAsString(student); System.out.println(jsonString); } catch (JsonParseException e) { e.printStackTrace(); } catch (JsonMappingException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } } class Student { private String name; private int age; public Student(){} public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String toString(){ return "Student [ name: "+name+", age: "+ age+ " ]"; } }
驗(yàn)證結(jié)果
使用javac編譯如下類:
C:\Jackson_WORKSPACE>javac JacksonTester.java
現(xiàn)在運(yùn)行jacksonTester看到的結(jié)果:
C:\Jackson_WORKSPACE>java JacksonTester
驗(yàn)證輸出
Student [ name: Mahesh, age: 21 ] { "name" : "Mahesh", "age" : 21 }
以下是這里要考慮的重要步驟。
創(chuàng)建ObjectMapper對(duì)象。它是一個(gè)可重復(fù)使用的對(duì)象。
ObjectMapper mapper = new ObjectMapper();
從JSON對(duì)象使用readValue()方法來(lái)獲取。通過(guò)JSON字符串和對(duì)象類型作為參數(shù)JSON字符串/來(lái)源。
//Object to JSON Conversion Student student = mapper.readValue(