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());  
    }  
}  

​

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