使用场景
我有一个5000条数据的json文件，每条数据包含地名、该地的经纬度等其他很多信息。现在想把地名和经纬度抽出来导入到数据库中。
navicat自带的导入json格式文件不好用，只能导入json文件中的外层数据，而我需要的地名和经纬度信息在json的内层。
抽取json指定字段值
json文件格式
{
"type": "FeatureCollection",
"features": [{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [117.135437, 39.22393]
},
"properties": {
"type": 1,
"OBJECTID": 9288,
"CC": "1117",
"GB": "310107",
"NAME": "某某村",
"PAC": "120104008006111",
"ELEMSTIME": "20150630",
"ELEMETIME": "",
"AREACODE": 120000,
"FEATID": 120000403,
"ChangeType": 0,
"ChangeAtt": ""
}
},
{
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [117.17052343, 39.124663697000074]
},
"properties": {
"OBJECTID": 9289,
"CC": "1117",
"GB": "310107",
"NAME": "某某社区",
"PAC": "120104003014111",
"ELEMSTIME": "20150630",
"ELEMETIME": "",
"AREACODE": 120000,
"FEATID": 120000458,
"ChangeType": 0,
"ChangeAtt": ""
}
}
]
}导入依赖
在pom.xml文件里加上fastjson
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.9</version>
</dependency>代码实现
读取本地json文件的方法
public static String readJsonFile(String fileName) {
String jsonStr = "";
try {
File jsonFile = new File(fileName);
FileReader fileReader = new FileReader(jsonFile);
Reader reader = new InputStreamReader(new FileInputStream(jsonFile), "utf-8");
int ch = 0;
StringBuffer sb = new StringBuffer();
while ((ch = reader.read()) != -1) {
sb.append((char) ch);
}
fileReader.close();
reader.close();
jsonStr = sb.toString();
return jsonStr;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}读取指定字段
先把json文件放在resourses下面（直接复制到resourses）
String path = ddem.class.getClassLoader().getResource("villagePoint.json").getPath();
String s = readJsonFile(path);
JSONObject jobj = JSON.parseObject(s);
JSONArray features = jobj.getJSONArray("features");//构建JSONArray数组
for (int i = 0; i < features.size(); i++) {
JSONObject key = (JSONObject) features.get(i);
JSONObject geometry =key.getJSONObject("geometry");
JSONArray coordinates=geometry.getJSONArray("coordinates");
BigDecimal jingdu = coordinates.getBigDecimal(0);
BigDecimal weidu = coordinates.getBigDecimal(1);
JSONObject properties=key.getJSONObject("properties");
String name =(String)properties.getString("NAME");
// System.out.println(jingdu);
// System.out.println(weidu);
System.out.println(name);
}JSONObject或JSONArray可以get很多种类型，具体用哪个看你自己的json内容
完整代码
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import java.io.*;
import java.math.BigDecimal;
public class ddem {
public static void main(String[] args) {
String path = ddem.class.getClassLoader().getResource("villagePoint.json").getPath();
String s = readJsonFile(path);
JSONObject jobj = JSON.parseObject(s);
JSONArray features = jobj.getJSONArray("features");//构建JSONArray数组
for (int i = 0; i < features.size(); i++) {
JSONObject key = (JSONObject) features.get(i);
JSONObject geometry =key.getJSONObject("geometry");
JSONArray coordinates=geometry.getJSONArray("coordinates");
BigDecimal jingdu = coordinates.getBigDecimal(0);
BigDecimal weidu = coordinates.getBigDecimal(1);
JSONObject properties=key.getJSONObject("properties");
String name =(String)properties.getString("NAME");
// System.out.println(jingdu);
// System.out.println(weidu);
System.out.println(name);
}
}
//读取json文件
public static String readJsonFile(String fileName) {
String jsonStr = "";
try {
File jsonFile = new File(fileName);
FileReader fileReader = new FileReader(jsonFile);
Reader reader = new InputStreamReader(new FileInputStream(jsonFile), "utf-8");
int ch = 0;
StringBuffer sb = new StringBuffer();
while ((ch = reader.read()) != -1) {
sb.append((char) ch);
}
fileReader.close();
reader.close();
jsonStr = sb.toString();
return jsonStr;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
}
把需要的数据整理到excel中
如上例所示，我需要地名和经纬度，可以一次性查出三列数据，但是为了复制到excel比较方便，我选择一个一个查出来，逐个复制到excel中，再为每列起个列名，就能非常方便地使用navicat的”导入xls“功能导入大量数据啦~
以上为个人经验，希望能给大家一个参考，也希望大家多多支持编程网。
