Java中过滤（截取）map的某个键值对包含map中嵌套的map

电玩女神 2023-07-17 06:34 127阅读 0赞

#### 主要使用的类：ObjectMapper ####

1，ObjectMapper的概述

*  ObjectMapper 是一个使用 Swift 语言编写的数据模型转换框架，我们可以方便的将模型对象转换为JSON，或者JSON生成相应的模型类

2，依赖的jar包

<dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.9.8</version>
    </dependency>

3，代码实现如下：

import com.fasterxml.jackson.annotation.JsonFilter;
    import com.fasterxml.jackson.core.JsonProcessingException;
    import com.fasterxml.jackson.databind.ObjectMapper;
    import com.fasterxml.jackson.databind.ser.impl.SimpleBeanPropertyFilter;
    import com.fasterxml.jackson.databind.ser.impl.SimpleFilterProvider;
    
    /** * JSON字符串过滤器 */
    public class JsonFilterSerializer { 
    
        private static final String DYNC_INCLUDE = "DYNC_INCLUDE";//包含的标识
        private static final String DYNC_EXCLUDE = "DYNC_EXCLUDE";//过滤的标识
    
        private ObjectMapper mapper = new ObjectMapper();
    
        @JsonFilter(DYNC_EXCLUDE)
        interface DynamicExclude { 
        }
    
        @JsonFilter(DYNC_INCLUDE)
        interface DynamicInclude { 
        }
    
        /** * * @param include 包含 * @param exclude 过滤 */
        public void filter(Class<?> clazz, String include, String exclude) { 
            if (clazz == null) return;
            if (include != null && include.length() > 0) { 
                mapper.setFilterProvider(new SimpleFilterProvider()
                        .addFilter(DYNC_INCLUDE, SimpleBeanPropertyFilter.filterOutAllExcept(include.split(","))));//多个字段用,分割开
                mapper.addMixIn(clazz, DynamicInclude.class);
            } else if (exclude != null && exclude.length() > 0) { 
                mapper.setFilterProvider(new SimpleFilterProvider()
                        .addFilter(DYNC_EXCLUDE, SimpleBeanPropertyFilter.serializeAllExcept(exclude.split(","))));
                mapper.addMixIn(clazz, DynamicExclude.class);
            }
        }
    
        public String toJson(Object object) throws JsonProcessingException { 
            return mapper.writeValueAsString(object);
        }
    
    }

4，测试用例：

@Test
        public void test01() throws JsonProcessingException { 
            Map<String, Object> maps = new HashMap();
            maps.put("name","Tommey周");
            maps.put("age", 100);
            maps.put("sex","男");
            Map<String, Object> map = new HashMap();
            map.put("deptno",1024);
            map.put("departName","研发部");
            map.put("departLevel",null);
            maps.put("depart",map);
            JsonFilterSerializer jsonFilter = new JsonFilterSerializer();
            jsonFilter.filter(Object.class,null,"depart");
            System.out.println("过滤map集合中的键值对 ---->"+jsonFilter.toJson(maps));//{"sex":"男","name":"Tommey周","age":100}
            jsonFilter.filter(Object.class,null,"departLevel");
            System.out.println("过滤map集合中的嵌套的键值对 ---->"+jsonFilter.toJson(maps));//{"sex":"男","name":"Tommey周","depart":{"deptno":1024,"departName":"研发部"},"age":100}
    // jsonFilter.filter(Object.class,"depart,deptno,departName",null);
    // System.out.println("截取map集合中的嵌套的键值对 ---->"+jsonFilter.toJson(maps));//{"depart":{"deptno":1024,"departName":"研发部"}}
        }