JSON 转换组合或对象，转换实体类类型

导包，jackson-core-2.8.10.jar

工具类

package com.ilyuc;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * json工具类(jackjson)
 */
public class JSONUtils {

	private final static ObjectMapper objectMapper = new ObjectMapper();

    private JSONUtils() {

    }

    public static ObjectMapper getInstance() {
        return objectMapper;
    }

    /**
     * object转化json
     * @param obj
     * @return
     * @throws Exception
     */
    public static String beanToJson(Object obj) {
        try {
			return objectMapper.writeValueAsString(obj);
		} catch (JsonProcessingException e) {
			e.printStackTrace();
		}
        return null;
    }

    /**
     * json转对象
     * @param jsonStr
     * @param clazz
     * @return
     * @throws Exception
     */
    public static <T> T jsonToBean(String jsonStr, Class<T> clazz) {
        try {
            return objectMapper.readValue(jsonStr, clazz);
        } catch (Exception e) {
			e.printStackTrace();
		}
        return null;
    }

    /**
     * json转map
     * @param jsonStr
     * @return
     * @throws Exception
     */
    @SuppressWarnings("unchecked")
	public static <T> Map<String, Object> jsonToMap(String jsonStr)
            throws Exception {
        return objectMapper.readValue(jsonStr, Map.class);
    }

    /**
     * json转map，指定类型
     * @param jsonStr
     * @param clazz
     * @return
     * @throws Exception
     */
    public static <T> Map<String, T> jsonToMap(String jsonStr, Class<T> clazz)
            throws Exception {
        Map<String, Map<String, Object>> map = objectMapper.readValue(jsonStr,
                new TypeReference<Map<String, T>>() {
                });
        Map<String, T> result = new HashMap<String, T>();
        for (Entry<String, Map<String, Object>> entry : map.entrySet()) {
            result.put(entry.getKey(), mapToBean(entry.getValue(), clazz));
        }
        return result;
    }

    /**
     * json数组转list，指定类型
     * @param jsonArrayStr
     * @param clazz
     * @return
     * @throws Exception
     */
    public static <T> List<T> jsonToList(String jsonArrayStr, Class<T> clazz)
            throws Exception {
        List<Map<String, Object>> list = objectMapper.readValue(jsonArrayStr,
                new TypeReference<List<T>>() {
                });
        List<T> result = new ArrayList<T>();
        for (Map<String, Object> map : list) {
            result.add(mapToBean(map, clazz));
        }
        return result;
    }

    /**
     * map转化对象
     */
    @SuppressWarnings("rawtypes")
	public static <T> T mapToBean(Map map, Class<T> clazz) {
        return objectMapper.convertValue(map, clazz);
    }
	
}

调用

List<NewEntity> newList = BeanConvert.objectConvertBean(oldList, NewEntity.class);

（完）

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