JSON 之 jackson 用法

Jackson简单用法一：

importjava.text.SimpleDateFormat; 

importjava.util.ArrayList; 

importjava.util.Date; 

importjava.util.HashMap; 

importjava.util.List; 

importjava.util.Map; 

 

import org.codehaus.jackson.JsonGenerator; 

importorg.codehaus.jackson.map.DeserializationConfig; 

importorg.codehaus.jackson.map.ObjectMapper; 

import org.codehaus.jackson.map.SerializationConfig; 

importorg.codehaus.jackson.map.annotate.JsonSerialize.Inclusion; 

importorg.codehaus.jackson.type.TypeReference;

 

import com.fasterxml.jackson.databind.DeserializationFeature;

 

import java.util.Date; 

 

public classJacksonTest { 

    public staticObjectMapper 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.setDateFormat(newSimpleDateFormat("yyyy-MM-ddHH:mm:ss")); 

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

       

        //设置有属性不能映射成PO时不报错 

        mapper.disable(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES); 

//     mapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES,false);  上一条也可以如此设置；

       

        return mapper; 

    } 

    public static voidmain(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 = newStudent(1,name1,"一班",newDate());   

        Student student2 = newStudent(2,name2,"二班",newDate());   

        Student student3 = newStudent(3,name3,"三班",newDate());   

       List studentList = new ArrayList(); 

        studentList.add(student1); 

        studentList.add(student2); 

        studentList.add(student3); 

       Map studentMap = new HashMap(); 

        studentMap.put("1", student1); 

        studentMap.put("2", student2); 

        studentMap.put("3", student3); 

        Student json2object = null; 

       List json2list = null; 

       Map 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