json转化的时候如何忽略某些属性字段值

一、有时候在将对象或list对象转化为json的时候，我们可能不需要所有的属性值，这就需要我们去过滤掉这些属性了

　　我下面说两种比较流行的json包如何来忽略某些属性值

二、 使用jaskson包

1.   maven配置：

        <!-- Jackson Json处理工具包 -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.5</version>
        </dependency>

2.  在需要忽略字段属性上使用注解来配置：

//@JsonIgnoreProperties({"dict_id","dict_item_code"}) // 可以使用此注解放在类上忽略多个属性值
public class BaseDict {
    @JsonIgnore  //可以直接放在field上面表示要忽略的filed
    private String dict_id;
    private String dict_type_code;
    private String dict_type_name;
    private String dict_item_name;
    private String dict_item_code;
    private Integer dict_sort;
    private String dict_enable;
    private String dict_memo;
    public String getDict_id() {
        return dict_id;
    }
    public void setDict_id(String dict_id) {
        this.dict_id = dict_id;
    }
    public String getDict_type_code() {
        return dict_type_code;
    }
    public void setDict_type_code(String dict_type_code) {
        this.dict_type_code = dict_type_code;
    }
    public String getDict_type_name() {
        return dict_type_name;
    }
    public void setDict_type_name(String dict_type_name) {
        this.dict_type_name = dict_type_name;
    }
    public String getDict_item_name() {
        return dict_item_name;
    }
    public void setDict_item_name(String dict_item_name) {
        this.dict_item_name = dict_item_name;
    }
    public String getDict_item_code() {
        return dict_item_code;
    }
    public void setDict_item_code(String dict_item_code) {
        this.dict_item_code = dict_item_code;
    }
    public Integer getDict_sort() {
        return dict_sort;
    }
    public void setDict_sort(Integer dict_sort) {
        this.dict_sort = dict_sort;
    }
    public String getDict_enable() {
        return dict_enable;
    }
    public void setDict_enable(String dict_enable) {
        this.dict_enable = dict_enable;
    }
    public String getDict_memo() {
        return dict_memo;
    }
    public void setDict_memo(String dict_memo) {
        this.dict_memo = dict_memo;
    }
    
}

3. 使用封装的jsonUtils来实现操作

package com.sshcrm.utils;

import java.util.List;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * CRM自定义响应结构
 */
public class JsonUtils {

    // 定义jackson对象
    private static final ObjectMapper MAPPER = new ObjectMapper();

    /**
     * 将对象转换成json字符串。
     * <p>Title: pojoToJson</p>
     * <p>Description: </p>
     * @param data
     * @return
     */
    public static String objectToJson(Object data) {
        try {
            String string = MAPPER.writeValueAsString(data);
            return string;
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return null;
    }
    
    /**
     * 将json结果集转化为对象
     * 
     * @param jsonData json数据
     * @param clazz 对象中的object类型
     * @return
     */
    public static <T> T jsonToPojo(String jsonData, Class<T> beanType) {
        try {
            T t = MAPPER.readValue(jsonData, beanType);
            return t;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
    
    /**
     * 将json数据转换成pojo对象list
     * <p>Title: jsonToList</p>
     * <p>Description: </p>
     * @param jsonData
     * @param beanType
     * @return
     */
    public static <T>List<T> jsonToList(String jsonData, Class<T> beanType) {
        JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType);
        try {
            List<T> list = MAPPER.readValue(jsonData, javaType);
            return list;
        } catch (Exception e) {
            e.printStackTrace();
        }
        
        return null;
    }
    
}

三、使用json-lib包

1.  maven配置

        <!--json-lib依赖 -->
        <dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>2.4</version>
            <classifier>jdk15</classifier>
        </dependency>

2.  使用JsonConfig指定要忽略的属性

    public String findByTypeCode() throws IOException {
        //调用业务层查询
        List<BaseDict> result = baseDictService.findByTypeCode(baseDict.getDict_type_code());
        //将list转化为json
        /**
         * JSONConfig: 转JSON的配置对象
         * JSONAarray：将数组和list集合转成JSON
         * JSONObject: 将对象和Map集合转成JSON
         */
        JsonConfig jsonConfig = new JsonConfig();
        jsonConfig.setExcludes(new String[] {"dict_sort","dict_enable","dict_memo"});
        JSONArray jsonArray = JSONArray.fromObject(result, jsonConfig);
        //将json打印到页面
        ServletActionContext.getResponse().setContentType("text/html;charset=utf-8");
        ServletActionContext.getResponse().getWriter().print(jsonArray.toString());
        return NONE;
    }