package com.inspur.demo.json;

import java.io.IOException;

import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Calendar;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import com.fasterxml.jackson.annotation.JsonInclude.Include;

import com.fasterxml.jackson.core.JsonGenerator;

import com.fasterxml.jackson.core.type.TypeReference;

import com.fasterxml.jackson.databind.BeanDescription;

import com.fasterxml.jackson.databind.JsonNode;

import com.fasterxml.jackson.databind.JsonSerializer;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.fasterxml.jackson.databind.SerializationConfig;

import com.fasterxml.jackson.databind.SerializerProvider;

import com.fasterxml.jackson.databind.ser.BeanPropertyWriter;

import com.fasterxml.jackson.databind.ser.BeanSerializerModifier;

/**

 * Jackson操作JSON数据

 */

public class JacksonCase {

    /**

     * 序列化

     */

    public static String serialize() {

        MyBean bean = new MyBean();

        bean.setS("测试字符串");

        Calendar calendar = Calendar.getInstance();

        calendar.add(Calendar.HOUR_OF_DAY, -1);

        bean.setD(calendar.getTime());

        List<MyBean> list = new ArrayList<MyBean>();

        list.add(bean);

        Map<String, List<MyBean>> map = new HashMap<String, List<MyBean>>();

        map.put("data", list);

        String result = "";

        try {

            ObjectMapper objectMapper = new ObjectMapper();

            //设置日期格式，也可在类属性上使用@JsonFormat(pattern="yyyy-MM-dd HH:mm:ss")来设置

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

            objectMapper.setSerializationInclusion(Include.ALWAYS);

            //字符串如果为null则输出""

            objectMapper.setSerializerFactory(objectMapper.getSerializerFactory().withSerializerModifier(new BeanSerializerModifier() {

                @Override

                public List<BeanPropertyWriter> changeProperties(SerializationConfig config, BeanDescription beanDesc, List<BeanPropertyWriter> beanProperties) {

                    for (BeanPropertyWriter writer : beanProperties) {

                        Class<?> clazz = writer.getType().getRawClass();

                        if (CharSequence.class.isAssignableFrom(clazz) || Character.class.isAssignableFrom(clazz)) {

                            writer.assignNullSerializer(new JsonSerializer<Object>() {

                                @Override

                                public void serialize(Object o, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {

                                    jsonGenerator.writeString("");

                                }

                            });

                        }

                    }

                    return beanProperties;

                }

            }));

            result = objectMapper.writeValueAsString(map);

            System.out.println(result);

        } catch (Exception e) {

            e.printStackTrace();

        }

        return result;

    }

    /**

     * 反序列化

     */

    public static void deserialize() {

        String s = serialize();

        try {

            ObjectMapper objectMapper = new ObjectMapper();

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

            TypeReference<Map<String, List<MyBean>>> type = new TypeReference<Map<String, List<MyBean>>>(){};

            Map<String, List<MyBean>> map = objectMapper.readValue(s, type);

            System.out.println(map);

            //树模型api

            JsonNode root = objectMapper.readTree(s);

            JsonNode bean = root.get("data").get(0);

            System.out.println(bean.get("s").asText());

            //...

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

    public static void main(String[] args) {

        serialize();

        deserialize();

    }

}

package com.inspur.demo.json;

import java.util.Arrays;

import java.util.Date;

public class MyBean {

    private String s = "字符串";

    private String s2;

    private String s3 = "字符串3";

    private int i = 123;

    private Integer i2;

    private char c = '到';

    private char[] c2 = new char[]{'a', 'b'};

    private Date d = new Date();

    private Date[] d2 = new Date[]{new Date(), new Date()};

    public String getS() {

        return s;

    }

    public void setS(String s) {

        this.s = s;

    }

    public String getS2() {

        return s2;

    }

    public void setS2(String s2) {

        this.s2 = s2;

    }

    public String getS3() {

        return s3;

    }

    public void setS3(String s3) {

        this.s3 = s3;

    }

    public int getI() {

        return i;

    }

    public void setI(int i) {

        this.i = i;

    }

    public Integer getI2() {

        return i2;

    }

    public void setI2(Integer i2) {

        this.i2 = i2;

    }

    public char getC() {

        return c;

    }

    public void setC(char c) {

        this.c = c;

    }

    public char[] getC2() {

        return c2;

    }

    public void setC2(char[] c2) {

        this.c2 = c2;

    }

    public Date getD() {

        return d;

    }

    public void setD(Date d) {

        this.d = d;

    }

    public Date[] getD2() {

        return d2;

    }

    public void setD2(Date[] d2) {

        this.d2 = d2;

    }

    @Override

    public String toString() {

        return "MyBean [s=" + s + ", s2=" + s2 + ", s3=" + s3 + ", i=" + i + ", i2=" + i2 + ", c=" + c + ", c2="

                + Arrays.toString(c2) + ", d=" + d + ", d2=" + Arrays.toString(d2) + "]";

    }

}