java读取JSON文件的多种实现方式
作者：csdn_halon
在开发过程中有时会遇到需要读取本地.json文件的需求，通常会自己写Reader代码去读，但是这么做写出来的代码有些繁琐（需要关流、创建StringBuilder对象等操作）。
最近发现几个小工具可以让需求代码变得更加简洁。
准备
json文件：F:\halon.json
{
"ID": 10001,
"detail": "detail",
"json_format_version": 1.0,
"other_info": {
"array_one": [
[855, 410],
[854, 411],
[847, 411],
[846, 410],
[845, 410],
[844, 409]
],
"array_two": [
[832, 303],
[829, 303],
[828, 302],
[825, 302],
[824, 301]
],
"array_three": [
[1013, 224],
[1012, 225],
[1010, 225],
[1009, 226],
[1023, 224]
],
"point": [853, 310],
"boolean": true
}
}
1.使用FileReader读取json文件
package com.tool;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Map;
/**
* @Author halon
* @create 2021/9/
*/
public class ReadLocalJsonFileDemo {
public static void main(String[] args) throws IOException {
File file = new File("F:\\halon.json");
readerMethod(file);
}
private static void readerMethod(File file) throws IOException {
FileReader fileReader = new FileReader(file);
Reader reader = new InputStreamReader(new FileInputStream(file), "Utf-8");
int ch = 0;
StringBuffer sb = new StringBuffer();
while ((ch = reader.read()) != -1) {
sb.append((char) ch);
}
fileReader.close();
reader.close();
String jsonStr = sb.toString();
System.out.println(JSON.parseObject(jsonStr));
}
}
控制台输出：
{"other_info":{"array_two":[[832,303],[829,303],[828,302],[825,302],[824,301]],"array_three":[[1013,224],[1012,225],[1010,225],[1009,226],[1023,224]],"boolean":true,"array_one":[[855,410],[854,411],[847,411],[846,410],[845,410],[844,409]],"point":[853,310]},"ID":10001,"detail":"detail","json_format_version":1.0}
2.使用jacksonAPI读取json文件
package com.tool;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Map;
/**
* @Author halon
* @create 2021/9/
*/
public class ReadLocalJsonFileDemo {
public static void main(String[] args) throws IOException {
File file = new File("F:\\halon.json");
jacksonMethod(file);
}
private static void jacksonMethod(File file) throws IOException {
ObjectMapper objectMapper = new ObjectMapper();
System.out.println(objectMapper.readValue(file, Map.class));
}
控制台输出：
{ID=10001, detail=detail, json_format_version=1.0, other_info={array_one=[[855, 410], [854, 411], [847, 411], [846, 410], [845, 410], [844, 409]], array_two=[[832, 303], [829, 303], [828, 302], [825, 302], [824, 301]], array_three=[[1013, 224], [1012, 225], [1010, 225], [1009, 226], [1023, 224]], point=[853, 310], boolean=true}}
3.使用nio读取json文件
package com.tool;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Map;
/**
* @Author halon
* @create 2021/9/
*/
public class ReadLocalJsonFileDemo {
public static void main(String[] args) throws IOException {
File file = new File("F:\\halon.json");
nioMethod(file);
}
private static void nioMethod(File file) throws IOException {
String jsonString = new String(Files.readAllBytes(Paths.get(file.getPath())));
System.out.println(JSONObject.parseObject(jsonString));
}
控制台输出：
{"other_info":{"array_two":[[832,303],[829,303],[828,302],[825,302],[824,301]],"array_three":[[1013,224],[1012,225],[1010,225],[1009,226],[1023,224]],"boolean":true,"array_one":[[855,410],[854,411],[847,411],[846,410],[845,410],[844,409]],"point":[853,310]},"ID":10001,"detail":"detail","json_format_version":1.0}
未完待续。。。。
总结
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脚本之家。