包含或排除指定的属性
import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.spring.PropertyPreFilters;
/**
* 使用FastJson将实体对象转换成Json字符串测试类
*/
public class FastJsonApplication {
public static void main(String[] args) {
User user = new User();
user.setId(1L);
user.setUsername("张三");
user.setPassword("");
user.setMobile(null);
user.setCountry("中国");
user.setCity("武汉");
String jsonUser = null;
/**
* 指定排除属性过滤器和包含属性过滤器
* 指定排除属性过滤器：转换成JSON字符串时，排除哪些属性
* 指定包含属性过滤器：转换成JSON字符串时，包含哪些属性
*/
String[] excludeProperties = {"country", "city"};
String[] includeProperties = {"id", "username", "mobile"};
PropertyPreFilters filters = new PropertyPreFilters();
PropertyPreFilters.MySimplePropertyPreFilter excludefilter = filters.addFilter();
excludefilter.addExcludes(excludeProperties);
PropertyPreFilters.MySimplePropertyPreFilter includefilter = filters.addFilter();
includefilter.addIncludes(includeProperties);
/**
* 情况一：默认忽略值为null的属性
*/
jsonUser = JSONObject.toJSONString(user, SerializerFeature.PrettyFormat);
System.out.println("情况一:\n" + jsonUser);
/**
* 情况二：包含值为null的属性
*/
jsonUser = JSONObject.toJSONString(user, SerializerFeature.PrettyFormat, SerializerFeature.WriteMapNullValue);
System.out.println("情况二:\n" + jsonUser);
/**
* 情况三：默认忽略值为null的属性，但是排除country和city这两个属性
*/
jsonUser = JSONObject.toJSONString(user, excludefilter, SerializerFeature.PrettyFormat);
System.out.println("情况三:\n" + jsonUser);
/**
* 情况四：包含值为null的属性，但是排除country和city这两个属性
*/
jsonUser = JSONObject.toJSONString(user, excludefilter, SerializerFeature.PrettyFormat, SerializerFeature.WriteMapNullValue);
System.out.println("情况四:\n" + jsonUser);
/**
* 情况五：默认忽略值为null的属性，但是包含id、username和mobile这三个属性
*/
jsonUser = JSONObject.toJSONString(user, includefilter, SerializerFeature.PrettyFormat);
System.out.println("情况五:\n" + jsonUser);
/**
* 情况六：包含值为null的属性，但是包含id、username和mobile这三个属性
*/
jsonUser = JSONObject.toJSONString(user, includefilter, SerializerFeature.PrettyFormat, SerializerFeature.WriteMapNullValue);
System.out.println("情况六:\n" + jsonUser);
}
/**
* 用户实体类
*/
public static class User {
private Long id;
private String username;
private String password;
private String mobile;
private String country;
private String city;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getMobile() {
return mobile;
}
public void setMobile(String mobile) {
this.mobile = mobile;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
}
}