解析Java的Jackson库中对象的序列化与数据泛型绑定

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+ " ]";  } }

import java.io.File;import java.io.IOException;import java.util.Arrays;import java.util.HashMap;import java.util.List;import java.util.Map;import org.codehaus.jackson.JsonGenerationException;import org.codehaus.jackson.JsonParseException;import org.codehaus.jackson.map.JsonMappingException;import org.codehaus.jackson.map.ObjectMapper;import org.codehaus.jackson.type.TypeReference;public class JacksonTester {  public static void main(String args[]){   JacksonTester tester = new JacksonTester();     try {      ObjectMapper mapper = new ObjectMapper();      Map userDataMap = new HashMap();      UserData studentData = new UserData();       int[] marks = {1,2,3};      Student student = new Student();      student.setAge(10);      student.setName("Mahesh");      // JAVA Object      studentData.setStudent(student);      // JAVA String      studentData.setName("Mahesh Kumar");      // JAVA Boolean      studentData.setVerified(Boolean.FALSE);      // Array      studentData.setMarks(marks);      TypeReference ref = new TypeReference>() { };      userDataMap.put("studentData1", studentData);      mapper.writeValue(new File("student.json"), userDataMap);      //{      //  "studentData1":      // {      // "student":      // {      //  "name":"Mahesh",      //  "age":10      //   },      //   "name":"Mahesh Kumar",      //   "verified":false,      //   "marks":[1,2,3]      //  }      //}      userDataMap = mapper.readValue(new File("student.json"), ref);      System.out.println(userDataMap.get("studentData1").getStudent());      System.out.println(userDataMap.get("studentData1").getName());      System.out.println(userDataMap.get("studentData1").getVerified());      System.out.println(Arrays.toString(userDataMap.get("studentData1").getMarks()));   } 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+ " ]";  } }class UserData {  private Student student;  private String name;  private Boolean verified;  private int[] marks;  public UserData(){}  public Student getStudent() {   return student;  }  public void setStudent(Student student) {   this.student = student;  }  public String getName() {   return name;  }  public void setName(String name) {   this.name = name;  }  public Boolean getVerified() {   return verified;  }  public void setVerified(Boolean verified) {   this.verified = verified;  }  public int[] getMarks() {   return marks;  }  public void setMarks(int[] marks) {   this.marks = marks;  } }

Student [ name: Mahesh, age: 10 ]Mahesh Kumarfalse[1, 2, 3]