jackson简单用法

转自：http://blog.csdn.net/hi_kevin/article/details/36639571

jackson简单用法

Name类：

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

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;}@Overridepublic String toString() {return "Student [birthDay=" + birthDay + ", id=" + id + ", name=" + name + ", classname="+ className + "]";}}

测试类：

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());}}