1：操作步骤

将Json文件读取为Json字符串--->根据JsonPath修改对应Path的value值---->格式化Json字符串---->将格式化后的Json字符串写入指定Json文件中

2：代码目录结构

|——cn.Demo.ReadJson  //Package
|————FileUtils.java   //将Json文件读取为字符串 将Json字符串写入文件
|————FormatJsonUtlis.java  //格式化Json字符串
|————RwJsonFileUtils.java //读写Json
|————Demo.json //演示Demo Json文件

3：导入Maven依赖

<!-- https://mvnrepository.com/artifact/org.json/json -->
<dependency>
	<groupId>org.json</groupId>
	<artifactId>json</artifactId>
	<version>20180813</version>
</dependency>

<dependency>
    <groupId>com.jayway.jsonpath</groupId>
    <artifactId>json-path</artifactId>
    <version>2.3.0</version>
</dependency>

4：代码实现

FileUtils.java

/**
 * @author Anndy
 * 
 * */
package cn.Demo.ReadJson;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;

public class FileUtils {
    /**
     * 以行为单位读取文件，常用于读面向行的格式化文件
     */
	public static String readJsonData(String pactFile){
		// 读取文件数据
		//System.out.println("读取文件数据util");
		
		StringBuffer strbuffer = new StringBuffer();
		File myFile = new File(pactFile);//"D:"+File.separatorChar+"DStores.json"
		if (!myFile.exists()) {
			System.err.println("Can't Find " + pactFile);
		}
		try {
			FileInputStream fis = new FileInputStream(pactFile);
			InputStreamReader inputStreamReader = new InputStreamReader(fis, "UTF-8");
			BufferedReader in  = new BufferedReader(inputStreamReader);
			
			String str;
			while ((str = in.readLine()) != null) {
				strbuffer.append(str);  //new String(str,"UTF-8")
			}
			in.close();
		} catch (IOException e) {
			e.getStackTrace();
		}
		//System.out.println("读取文件结束util");
		return strbuffer.toString();

	}
	
	// 把json格式的字符串写到文件
    public static boolean writeFile(String filePath, String sets) {
        FileWriter fw;
        try {
            fw = new FileWriter(filePath);
            PrintWriter out = new PrintWriter(fw);
            out.write(sets);
            out.println();
            fw.close();
            out.close();
            return true;
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        }

    }
	
}

FormatJsonUtlis.java

package cn.Demo.ReadJson;

/**
 * 格式化输入工具类
 * 
 */
public class FormatJsonUtlis {

    /**
     * 格式化
     * 
     * @author Anndy
     */
    public static String formatJson(String jsonStr) {
        if (null == jsonStr || "".equals(jsonStr))
            return "";
        StringBuilder sb = new StringBuilder();
        char last = '\0';
        char current = '\0';
        int indent = 0;
        boolean isInQuotationMarks = false;
        for (int i = 0; i < jsonStr.length(); i++) {
            last = current;
            current = jsonStr.charAt(i);
            switch (current) {
            case '"':
                                if (last != '\\'){
                    isInQuotationMarks = !isInQuotationMarks;
                                }
                sb.append(current);
                break;
            case '{':
            case '[':
                sb.append(current);
                if (!isInQuotationMarks) {
                    sb.append('\n');
                    indent++;
                    addIndentBlank(sb, indent);
                }
                break;
            case '}':
            case ']':
                if (!isInQuotationMarks) {
                    sb.append('\n');
                    indent--;
                    addIndentBlank(sb, indent);
                }
                sb.append(current);
                break;
            case ',':
                sb.append(current);
                if (last != '\\' && !isInQuotationMarks) {
                    sb.append('\n');
                    addIndentBlank(sb, indent);
                }
                break;
            default:
                sb.append(current);
            }
        }

        return sb.toString();
    }

    /**
     * 添加space
     * 
     */
    private static void addIndentBlank(StringBuilder sb, int indent) {
        for (int i = 0; i < indent; i++) {
            sb.append('\t');
        }
    }
}

RwJsonFileUtils.java

package cn.Demo.ReadJson;

import com.jayway.jsonpath.DocumentContext;
import com.jayway.jsonpath.JsonPath;

public class RwJsonFileUtils{
	
	public static void main(String[] args) {
		
		String filePath = "G:\\workspace1\\ReadJson\\src\\main\\java\\cn\\Demo\\ReadJson\\Demo.json";
		
		//将Json文件读取为字符串
		String json = FileUtils.readJsonData("G:\\workspace1\\ReadJson\\src\\main\\java\\cn\\Demo\\ReadJson\\Demo.json");
        
		//修改Json的value
		DocumentContext context = JsonPath.parse(json);
		
		JsonPath path = JsonPath.compile("$.result.records[0].name");
		
		context.set(path, "修改成功了");
		
		String changedJson = context.jsonString();

		//将json字符串格式化 并写入制定文件
		FileUtils.writeFile(filePath, FormatJsonUtlis.formatJson(changedJson));
		
		String read = (String)JsonPath.read(changedJson, "$.result.records[1].mobile");
        
        System.out.println(read.toString());

	}
}

Demo.json

{
	"action":"/interface.service/xxx/queryBlackUserData",
	"all":"1",
	"result":{
		"count":2,
		"tenant_count":2,
		"records":[
			{
				"name":"修改成功了",
				"pid":"500234199212121212",
				"mobile":"18623456789",
				"applied_at":"3",
				"confirmed_at":"5",
				"confirm_type":"overdue",
				"loan_type":1,
				"test":"mytest",
				"all":"2"
			},
			{
				"name":"李四",
				"pid":"500234199299999999",
				"mobile":"13098765432",
				"applied_at":"1",
				"confirmed_at":"",
				"confirm_type":"overdue",
				"loan_type":3,
				"all":"3"
			},
			{
				"name":"王五",
				"pid":"50023415464654659",
				"mobile":"1706454894",
				"applied_at":"-1",
				"confirmed_at":"",
				"confirm_type":"overdue",
				"loan_type":3
			}
		],
		"all":"4"
	},
	"code":200,
	"subtime":"1480495123550",
	"status":"success",
	"ok":3
}