@JsonIgnore，@JsonFormat 等标签使用

1. @JsonIgnore  作用是 json序列化时Bean中的属性会被忽略。

2. @JsonFormat  作用是json序列化时格式化Bean中的属性输出的格式（如：Date）

3.@JsonSerialize 作用是json序列化时按照自己定义的格式方法执行。

 

如：

package com.boce.test;

 

import java.io.Serializable;

import java.util.Date;

 

import com.fasterxml.jackson.annotation.JsonFormat;

import com.fasterxml.jackson.annotation.JsonIgnore;

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

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.fasterxml.jackson.databind.annotation.JsonSerialize;

import com.ibm.icu.util.Calendar;

 

public class Person implements Serializable {

 

private String name;

@JsonIgnore

private String sex;

@JsonFormat(pattern="yyyy-MM-dd HH:mm:ss")

private Date birday;

 

@JsonSerialize(using=DoubleFormat.class)

private Double weight;

 

public String getName() {

return name;

}

 

public void setName(String name) {

this.name = name;

}

 

public String getSex() {

return sex;

}

 

public void setSex(String sex) {

this.sex = sex;

}

 

public Date getBirday() {

return birday;

}

 

public void setBirday(Date birday) {

this.birday = birday;

}

 

public Double getWeight() {

return weight;

}

 

public void setWeight(Double weight) {

this.weight = weight;

}

 

public static void main(String[] args) {

 

Person p = new Person();

p.setName("boce");

p.setSex("man");

p.setBirday(Calendar.getInstance().getTime());

p.setWeight(150.2);

 

String result ="";

ObjectMapper mapper = new ObjectMapper();

// 配置mapper忽略空属性

mapper.setSerializationInclusion(Include.NON_EMPTY);

// 默认情况，Jackson使用Java属性字段名称作为 Json的属性名称,也可以使用Jackson

try {

result = mapper.writeValueAsString(p);

} catch (JsonProcessingException e) {

e.printStackTrace();

}

 

System.out.println(result);

 

 

 

}

 

}

 

 

格式化double 数据为 ###.00 ,有两位有效数字.

package com.boce.test;

 

import java.io.IOException;

import java.text.DecimalFormat;

 

import com.fasterxml.jackson.core.JsonGenerator;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.JsonSerializer;

import com.fasterxml.jackson.databind.SerializerProvider;

 

/**

 * double 数据格式化为 ****.00;

 * @author dell

 *

 */

public class DoubleFormat extends JsonSerializer<Double>{

 

DecimalFormat df = new DecimalFormat("###.00");

@Override

public void serialize(Double value, JsonGenerator gen, SerializerProvider serializers)

throws IOException, JsonProcessingException {

if(value !=null){

gen.writeString(df.format(value));

}

 

}

 

}

 

 

输出结果：

{"name":"boce","birday":"2017-02-22 03:16:01","weight":"150.20"}

 

说明：sex 没有在json字符串中出现。

birday，weight 已经被格式化