JSON解析方法总结

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解析JSON常用jar包

        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.7</version>
        </dependency>

        <dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>2.4</version>
            <classifier>jdk15</classifier>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.46</version>
        </dependency>

        <dependency>
            <groupId>org.json</groupId>
            <artifactId>json</artifactId>
            <version>20160810</version>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-io</artifactId>
            <version>1.3.2</version>
        </dependency>

示例代码

1.读取.json文件中的内容

将文件中的内容以字符串的形式读出,用了org.apache.commons.io的jar包

String str= FileUtils.readFileToString(file, "UTF-8");

2.将json字符串转换成map

利用map,com.alibaba.fastjson;

Map jsonMap = JSON.parseObject(str);

 3.将map转换成json对象格式,将json对象转换为字符串

利用org.json

JSONObject json =new JSONObject(jsonMap);
String jsonString = json.toString();

 代码示例

import com.alibaba.fastjson.JSON;
import org.apache.commons.io.FileUtils;
import org.json.JSONObject;

import java.io.*;
import java.util.Map;

public class JsonTest {

    public static void main(String[] args) {

        File files = new File("D:\\jsonTest");
        String[] fileName = files.list();

        for (int i = 0; i < fileName.length; i++) {
            String path = "D:\\jsonTest\\" + fileName[i];
            File file = new File(path);

            try {

                //将文件中的内容以字符串形式读出,org.apache.commons.io;
                String str= FileUtils.readFileToString(file, "UTF-8");
                //将json字符串转成map,com.alibaba.fastjson;
                Map jsonMap = JSON.parseObject(str);

                jsonMap.put("age",25);

                //将map转换成json对象格式,org.json;
                JSONObject json =new JSONObject(jsonMap);
                String jsonString = json.toString();


                String newPath =  "D:\\jsonTest2\\" +fileName[i];
                File newfile = new File(newPath);
                newfile.createNewFile();

                Writer write = new OutputStreamWriter(new FileOutputStream(newfile), "UTF-8");
                write.write(jsonString);
                write.flush();
                write.close();

                String name = fileName[i];
                String headName = name.substring(name.lastIndexOf('\\') + 1, name.indexOf('.'));
                String fullPath = "D:\\jsontxt\\" +headName+".txt";
                File txtfile = new File(fullPath);
                txtfile.createNewFile();

                FileWriter  out=new FileWriter (txtfile);
                BufferedWriter bw= new BufferedWriter(out);

                Map<String,String> hehe = jsonMap;
                String line1Param = hehe.getOrDefault("order1","").toString();
                String line2Param = hehe.getOrDefault("order2","").toString();
                String line3Param = hehe.getOrDefault("order3","").toString();
                String line4Param = hehe.getOrDefault("order4","").toString();

                bw.write(line1Param);
                //BufferedWriter提供的换行
                bw.newLine();
                bw.write(line2Param);
                bw.newLine();
                bw.write(line3Param);
                bw.newLine();
                bw.write(line4Param);

                bw.flush();
                bw.close();

            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

}