JSON格式化着色小工具

在我们系统开发过程中越来越多的使用JSON作为数据交换的载体。JSON的特点是层次结构简洁清晰，易于人阅读和编写。同时也易于机器解析和生成。对于机器解析和生成这点本人表示认可，然而对于易于人阅读和编写可以通过下面一段JSON字符串来验证下：

{"strValue":"here is str value","nullValue":null,"intvalue":999,"doublevalue":999,"booleanValue":true,"array":["a1","a2",true,2,33.3,null,{"innerStr":"here is a inner str","innerInteger":123456789},["Hi, found me ?"]],"innerOBJ":{"innerStr":"here is a inner str","innerInteger":123456789}}

通过上面的字符串可以看到系统间交换数据的JSON字符串通常是去除了格式的，这样的JSON我们阅读起来貌似并不是那么轻松。在网上有很多JSON格式和着色的插件，借助这些插件可以将JSON字符串进行格式化，这时候JSON的易于人阅读才表现出来。

{
      "strValue": "here is str value",
      "nullValue": null,
      "intvalue": 999,
      "doublevalue": 999,
      "booleanValue": true,
      "array": [
            "a1",
            "a2",
            true,
            2,
            33.3,
            null,
            {
                  "innerStr": "here is a inner str",
                  "innerInteger": 123456789
            },
            [
                  "Hi, found me ?"
            ]
      ],
      "innerOBJ": {
            "innerStr": "here is a inner str",
            "innerInteger": 123456789
      }
}

网上有很多JSON格式和着色的插件，找了一圈都是JS编写的，没有发现C/S的小工具。于是偶尔强迫症发作决定整一个小工具，下面直接上图：

主要的业务代码即为下面的工具类，提供了JSON校验、格式化、着色、删除空格、删除空格并转义、去除转义等功能。

import java.io.FileReader;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

/**
 * JSON格式化工具
 * @author StarlightFu
 *
 */
public class JsonFormatUtil {
    private static final String OBJECT_BRACE_REG = "([\\{\\}])";
    private static final String ARRAY_BRACE_REG = "([\\[\\]])";
    private static final String PROPERTY_NAME_REG = "(\\\".*\\\")(\\:)(.*)(\\,)?";
    private static final String STRING_REG = "\\\"([^\"]*)\\\"(\\,)?$";
    private static final String NUMBER_REG = "(-?\\d+)(\\,)?$";

    /** JSON着色样式 */
    public static final String JSON_STYLE = "<style>pre{font-family:\"微软雅黑\";font-size:10px;}.ObjectBrace{color:#00AA00;font-weight:bold;}.ArrayBrace{color:#0033FF;font-weight:bold;}"
            + ".PropertyName{color:#CC0000;font-weight:bold;}.String{color:#007777;}.Number{color:#AA00AA;}.Boolean{color:#0000FF;}"
            + ".Function{color:#AA6633;text-decoration:italic;}.Null{color:#0000FF;}.Comma{color:#000000;font-weight:bold;</style>";

    /**
     * 校验JSON格式是否正确
     * @param json JSON字符串
     * @return true:格式正确;false:格式错误
     */
    public static boolean validation(String json){
        boolean result = false;
        FileReader reader = null;
        try {
            String valJson = "function valJson(jsonStr){var result=false;try{eval(‘(‘+jsonStr+‘)‘);result=true;}catch(e){result=false;}return result;}";
            ScriptEngineManager manager = new ScriptEngineManager();
            ScriptEngine engine = manager.getEngineByName("javascript");
            engine.eval(valJson);

            if (engine instanceof Invocable) {
                Invocable invoke = (Invocable) engine;
                result = (Boolean) invoke.invokeFunction("valJson", json);
            }
        } catch (ScriptException e) {
            throw new ServiceException("执行JSON校验JS异常");
        } catch (NoSuchMethodException e) {
            throw new ServiceException("执行JSON校验JS异常");
        } finally {
            try {
                if (reader != null) {
                    reader.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }

    /**
     * 格式化JSON字符串
     * @param jsonStr
     * @return
     * @throws ServiceException
     */
    public static String format(String jsonStr)throws ServiceException{
        boolean valResult = false;
        valResult = JsonFormatUtil.validation(jsonStr);
        if (!valResult) {
            throw new ServiceException("JSON格式错误");
        }
        if (null == jsonStr || "".equals(jsonStr))
            return "";
        StringBuilder sb = new StringBuilder();
        char last = ‘\0‘;
        char current = ‘\0‘;
        int indent = 0;
        boolean inString = false;
        char inStringBegin = ‘\0‘;
        for (int i = 0; i < jsonStr.length(); i++) {
            last = current;
            current = jsonStr.charAt(i);
            if (inString && current == inStringBegin) {
                // 判断前一个字符是否为 \
                if (last != ‘\\‘) {
                    inString = false;
                    inStringBegin = ‘\0‘;
                }
                sb.append(current);
            } else if (!inString && (current == ‘"‘ || current == ‘\‘‘)) {
                inString = true;
                inStringBegin = current;
                sb.append(current);
            } else if (!inString && (current == ‘ ‘ || current == ‘\t‘ || current == ‘\n‘)) {
                current = ‘\0‘;
            } else if (!inString && current == ‘:‘) {
                sb.append(current).append(" ");
            } else if (!inString && current == ‘,‘) {
                sb.append(current).append(‘\n‘).append(indentBlank(indent));
            } else if (!inString && (current == ‘[‘ || current == ‘{‘)) {
                indent++;
                sb.append(current).append(‘\n‘).append(indentBlank(indent));
            } else if (!inString && (current == ‘]‘ || current == ‘}‘)) {
                indent--;
                sb.append(‘\n‘).append(indentBlank(indent)).append(current);
            } else {
                sb.append(current);
            }
        }
        return sb.toString();
    }

    /**
     * 添加缩进
     * @param indent
     * @return
     */
    private static String indentBlank(int indent) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < indent; i++) {
            sb.append("      ");
        }
        return sb.toString();
    }

    /**
     * JSON语法着色
     * @param formatJsonStr 格式化后的JSON字符串
     * @return
     */
    public static String coloring(String formatJsonStr) {
        StringBuilder sb = new StringBuilder();
        String[] nodes = formatJsonStr.split("\n");
        for (int i = 0; i < nodes.length; i++) {
            String node = nodes[i];

            Pattern r = Pattern.compile(JsonFormatUtil.OBJECT_BRACE_REG);
            Matcher m = r.matcher(node);
            node = m.replaceAll("<span class=‘ObjectBrace‘>$1</span>");

            r = Pattern.compile(JsonFormatUtil.ARRAY_BRACE_REG);
            m = r.matcher(node);
            node = m.replaceAll("<span class=‘ArrayBrace‘>$1</span>");

            r = Pattern.compile(JsonFormatUtil.PROPERTY_NAME_REG);
            m = r.matcher(node);
            node = m.replaceAll("<span class=‘PropertyName‘>$1</span>$2$3$4");

            r = Pattern.compile(JsonFormatUtil.STRING_REG);
            m = r.matcher(node);
            node = m.replaceAll("<span class=‘String‘>\"$1\"</span><span class=‘Comma‘>$2</span>");

            r = Pattern.compile(JsonFormatUtil.NUMBER_REG);
            m = r.matcher(node);
            node = m.replaceAll("<span class=‘Number‘>$1</span><span class=‘Comma‘>$2</span>");

            sb.append(node);
            if (i < nodes.length - 1) {
                sb.append("\n");
            }
        }
        return sb.toString();
    }

    /**
     * 格式化JSON并着色
     * @param json
     * @return
     */
    public static String formatAndColoring(String json){
        return JsonFormatUtil.coloring(JsonFormatUtil.format(json));
    }

    /**
     * 删除空格
     * @param jsonStr
     * @return
     */
    public static String removeSpace(String jsonStr){
        StringBuilder sb = new StringBuilder();
        char last = ‘\0‘;
        char current = ‘\0‘;
        char inStringBegin = ‘\0‘;
        boolean inString = false;
        for (int i = 0; i < jsonStr.length(); i++) {
            last = current;
            current = jsonStr.charAt(i);
            if (inString && current == inStringBegin) {
                // 判断前一个字符是否为 \
                if (last != ‘\\‘) {
                    inString = false;
                    inStringBegin = ‘\0‘;
                }
                sb.append(current);
            } else if (!inString && (current == ‘"‘ || current == ‘\‘‘)) {
                inString = true;
                inStringBegin = current;
                sb.append(current);
            } else if (!inString && (current == ‘ ‘ || current == ‘\t‘ || current == ‘\n‘)) {
                current = ‘\0‘;
            }else{
                sb.append(current);
            }
        }
        return sb.toString();
    }

    /**
     * 删除空格并转义
     * @param jsonStr
     * @return
     */
    public static String removeSpaceAndEscape(String jsonStr){
        jsonStr = JsonFormatUtil.removeSpace(jsonStr);
        return jsonStr.replaceAll("\"", "\\\\\"");
    }

    /**
     * 去除转义
     * @param jsonStr
     * @return
     */
    public static String removeEscape(String jsonStr){
        return jsonStr.replaceAll("\\\\\"", "\"");
    }

    public static void main(String[] args) {
        String jsonStr = "{\"strValue\":\"here is str value\",\"nullValue\":null,\"intvalue\":999,\"doublevalue\":999,\"booleanValue\":true,\"array\":[\"a1\",\"a2\",true,2,33.3,null,{\"innerStr\":\"here is a inner str\",\"innerInteger\":123456789},[\"Hi, found me ?\"]],\"innerOBJ\":{\"innerStr\":\"here is a inner str\",\"innerInteger\":123456789}}";
        System.out.println(JsonFormatUtil.format(jsonStr));
        System.out.println(JsonFormatUtil.coloring(JsonFormatUtil.format(jsonStr)));
    }
}

下面分享下基于上述代码实现的桌面小应用，有兴趣的同学可以下载，URL：JSON格式化小工具