Jackson全數據綁定

完全數據綁定是指JSON映射到任何Java對象。

//Create an ObjectMapper instance ObjectMapper mapper = new ObjectMapper(); //map JSON content to Student object Student student = mapper.readValue(new File("student.json"), Student.class); //map Student object to JSON content mapper.writeValue(new File("student.json"), student);

讓我們來看看簡單的數據操作綁定。在這裏，我們將直接映射Java對象到JSON，反之亦然。

創建一個名爲JacksonTester在Java類文件目錄 C:\>Jackson_WORKSPACE.

File: JacksonTester.java

import java.io.File; import java.io.IOException; import org.codehaus.jackson.JsonGenerationException; import org.codehaus.jackson.JsonParseException; import org.codehaus.jackson.map.JsonMappingException; import org.codehaus.jackson.map.ObjectMapper; public class JacksonTester { public static void main(String args[]){ JacksonTester tester = new JacksonTester(); try { Student student = new Student(); student.setAge(10); student.setName("Mahesh"); tester.writeJSON(student); Student student1 = tester.readJSON(); System.out.println(student1); } catch (JsonParseException e) { e.printStackTrace(); } catch (JsonMappingException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } private void writeJSON(Student student) throws JsonGenerationException, JsonMappingException, IOException{ ObjectMapper mapper = new ObjectMapper(); mapper.writeValue(new File("student.json"), student); } private Student readJSON() throws JsonParseException, JsonMappingException, IOException{ ObjectMapper mapper = new ObjectMapper(); Student student = mapper.readValue(new File("student.json"), Student.class); return student; } } 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+ " ]"; } }

驗證結果

使用javac編譯如下類：

C:\Jackson_WORKSPACE>javac JacksonTester.java

現在運行jacksonTester看到的結果：

C:\Jackson_WORKSPACE>java JacksonTester

驗證輸出

Student [ name: Mahesh, age: 10 ]