Json解析工具Jackson

• @JsonIgnoreProperties

  此注解是类注解，作用是json序列化时将Java bean中的一些属性忽略掉，序列化和反序列化都受影响。

• @JsonIgnore

  此注解用于属性或者方法上（最好是属性上），作用和上面的@JsonIgnoreProperties一样。

• @JsonFormat

  此注解用于属性或者方法上（最好是属性上），可以方便的把Date类型直接转化为我们想要的模式，比如@JsonFormat(pattern = "yyyy-MM-dd HH-mm-ss")

• @JsonSerialize

  此注解用于属性或者getter方法上，用于在序列化时嵌入我们自定义的代码，比如序列化一个double时在其后面限制两位小数点。

public class CustomDoubleSerialize extends JsonSerializer<Double> {  
  
    private DecimalFormat df = new DecimalFormat("##.00");  
  
    @Override  
    public void serialize(Double value, JsonGenerator jgen,  
            SerializerProvider provider) throws IOException,  
            JsonProcessingException {  
  
        jgen.writeString(df.format(value));  
    }  
}  

• @JsonDeserialize

  此注解用于属性或者setter方法上，用于在反序列化时可以嵌入我们自定义的代码，类似于上面的@JsonSerialize

public class CustomDateDeserialize extends JsonDeserializer<Date> {  
  
    private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");  
  
    @Override  
    public Date deserialize(JsonParser jp, DeserializationContext ctxt)  
            throws IOException, JsonProcessingException {  
  
        Date date = null;  
        try {  
            date = sdf.parse(jp.getText());  
        } catch (ParseException e) {  
            e.printStackTrace();  
        }  
        return date;  
    }  
}  

完整例子:

//表示序列化时忽略的属性  
@JsonIgnoreProperties(value = { "word" })  
public class Person {  
   private String name;  
   private int age;  
   private boolean sex;  
   private Date birthday;  
   private String word;  
   private double salary;  
 
   public String getName() {  
       return name;  
   }  
 
   public void setName(String name) {  
       this.name = name;  
   }  
 
   public int getAge() {  
       return age;  
   }  
 
   public void setAge(int age) {  
       this.age = age;  
   }  
 
   public boolean isSex() {  
       return sex;  
   }  
 
   public void setSex(boolean sex) {  
       this.sex = sex;  
   }  
 
   public Date getBirthday() {  
       return birthday;  
   }  
 
   // 反序列化一个固定格式的Date  
   @JsonDeserialize(using = CustomDateDeserialize.class)  
   public void setBirthday(Date birthday) {  
       this.birthday = birthday;  
   }  
 
   public String getWord() {  
       return word;  
   }  
 
   public void setWord(String word) {  
       this.word = word;  
   }  
 
   // 序列化指定格式的double格式  
   @JsonSerialize(using = CustomDoubleSerialize.class)  
   public double getSalary() {  
       return salary;  
   }  
 
   public void setSalary(double salary) {  
       this.salary = salary;  
   }  
 
   public Person(String name, int age) {  
       this.name = name;  
       this.age = age;  
   }  
 
   public Person(String name, int age, boolean sex, Date birthday,  
           String word, double salary) {  
       super();  
       this.name = name;  
       this.age = age;  
       this.sex = sex;  
       this.birthday = birthday;  
       this.word = word;  
       this.salary = salary;  
   }  
 
   public Person() {  
   }  
 
   @Override  
   public String toString() {  
       return "Person [name=" + name + ", age=" + age + ", sex=" + sex  
               + ", birthday=" + birthday + ", word=" + word + ", salary="  
               + salary + "]";  
   }  
 
}