Jackson简单用法

jackson简单用法

Name类：

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public class Name {

private String firstName;

private String lastName;

public Name(){}

public Name(String firstName, String lastName) {

this.firstName = firstName;

this.lastName = lastName;

}

public String getFirstName() {

return firstName;

}

public void setFirstName(String firstName) {

this.firstName = firstName;

}

public String getLastName() {

return lastName;

}

public void setLastName(String lastName) {

this.lastName = lastName;

}

public String toString() {

return firstName + " " + lastName;

}

}

Student类：

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import java.util.Date;

public class Student {

private int id;

private Name name;

private String className;

private Date birthDay;

public Student(){}

public Student(int id, Name name, String className, Date birthDay) {

super();

this.id = id;

this.name = name;

this.className = className;

this.birthDay = birthDay;

}

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public Name getName() {

return name;

}

public void setName(Name name) {

this.name = name;

}

public Date getBirthDay() {

return birthDay;

}

public void setBirthDay(Date birthDay) {

this.birthDay = birthDay;

}

public String getClassName() {

return className;

}

public void setClassName(String className) {

this.className = className;

}

@Override

public String toString() {

return "Student [birthDay=" + birthDay + ", id=" + id + ", name=" + name + ", classname="+ className + "]";

}

}

测试类

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import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Date;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import org.codehaus.jackson.JsonGenerator;

import org.codehaus.jackson.map.DeserializationConfig;

import org.codehaus.jackson.map.ObjectMapper;

import org.codehaus.jackson.map.SerializationConfig;

import org.codehaus.jackson.map.annotate.JsonSerialize.Inclusion;

import org.codehaus.jackson.type.TypeReference;

public class JacksonTest {

public static ObjectMapper getDefaultObjectMapper() {

ObjectMapper mapper = new ObjectMapper();

//设置将对象转换成JSON字符串时候:包含的属性不能为空或"";

//Include.Include.ALWAYS 默认

//Include.NON_DEFAULT 属性为默认值不序列化

//Include.NON_EMPTY 属性为 空（""） 或者为 NULL 都不序列化

//Include.NON_NULL 属性为NULL 不序列化

mapper.setSerializationInclusion(Inclusion.NON_EMPTY);

//设置将MAP转换为JSON时候只转换值不等于NULL的

mapper.configure(SerializationConfig.Feature.WRITE_NULL_MAP_VALUES, false);

mapper.configure(JsonGenerator.Feature.ESCAPE_NON_ASCII, true);

mapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));

//设置有属性不能映射成PO时不报错

mapper.disable(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES);

return mapper;

}

public static void main(String[] args) throws Exception{

//准备数据

Name name1 = new Name("zhang","san");

Name name2 = new Name("li","si");

Name name3 = new Name("wang","wu");

Student student1 = new Student(1,name1,"一班",new Date());

Student student2 = new Student(2,name2,"二班",new Date());

Student student3 = new Student(3,name3,"三班",new Date());

List<Student> studentList = new ArrayList<Student>();

studentList.add(student1);

studentList.add(student2);

studentList.add(student3);

Map<String,Student> studentMap = new HashMap<String, Student>();

studentMap.put("1", student1);

studentMap.put("2", student2);

studentMap.put("3", student3);

Student json2object = null;

List<Student> json2list = null;

Map<String,Student> json2map = null;

ObjectMapper mapper = getDefaultObjectMapper();

/* Object --> JSON */

String object4json = mapper.writeValueAsString(student1);

System.out.println("Object ----> JSON");

System.out.println(object4json);

System.out.println("------------------------------------------------------");

/* List<Object> --> JSON */

String listforjson = mapper.writeValueAsString(studentList);

System.out.println("List<Object> ----> JSON");

System.out.println(listforjson);

System.out.println("------------------------------------------------------");

/* Map<String,Object> ----> JSON */

String map4json = mapper.writeValueAsString(studentMap);

System.out.println("Map<String,Object> ----> JSON");

System.out.println(map4json);

System.out.println("------------------------------------------------------");

/* JSON --> Object */

json2object = mapper.readValue(object4json, Student.class);

System.out.println("JSON ----> Object");

System.out.println(json2object);

System.out.println("------------------------------------------------------");

/* JSON --> List<Object> */

json2list = mapper.readValue(listforjson, new TypeReference<List<Student>>() {});

System.out.println("JSON --> List<Object>");

System.out.println(json2list.toString());

System.out.println("------------------------------------------------------");

/* JSON --> Map<String,Object> */

json2map = mapper.readValue(map4json, new TypeReference<Map<String,Student>>() {});

System.out.println("JSON --> Map<String,Object>");

System.out.println(json2map.toString());

}

}