优雅的将Map转为String工具类

import com.alibaba.fastjson.JSONObject;
import org.apache.commons.lang3.StringUtils; import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors; /**
* Created by hujunzheng on 2017/7/20.
*/
public class MapToStringUtil { public static String toEqualString(Map<?, ?> map, char separator) {
List<String> result = new ArrayList<>();
map.entrySet().parallelStream().reduce(result, (first, second)->{
first.add(second.getKey() + "=" + second.getValue());
return first;
}, (first, second)->{
if (first == second) {
return first;
}
first.addAll(second);
return first;
}); return StringUtils.join(result, separator);
} public static Map<String, String> maptoMapString(Map<String, ?> map) {
return map.entrySet().stream().collect(Collectors.toMap(
(entry) -> {
return entry.getKey();
},
(entry) -> {
if(entry.getValue().getClass().isArray()) {
StringBuilder sb = new StringBuilder();
for(int i=0; i<Array.getLength(entry.getValue()); ++i) {
Object obj = Array.get(entry.getValue(), i);
sb.append(obj.toString()).append(",");
}
if (sb.length() > 0) {
sb.deleteCharAt(sb.length() - 1);
} return sb.toString();
} else {
return entry.getValue().toString();
}
}
));
} public static void main(String[] args) {
JSONObject jsonObject = new JSONObject();
jsonObject.put("name", "hjz");
jsonObject.put("age", 25); System.out.println(MapToStringUtil.toEqualString(jsonObject, ','));
}
}

输出结果

name=hjz,age=25

参考:java8 reduce方法中的第三个参数combiner有什么作用?

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