Java 讀寫json格式的文件方法詳解

public class ElectSet {
    public String xueqi;
    public String xuenian;
    public String startTime;
    public String endTime;
    public int menshu;
    public String isReadDB;

// {"xueqi":,"xuenian":,"startTime":,"endTime":,"renshu":,"isReadDB":}
    public String getXueqi() {
        return xueqi;
    }

    public void setXueqi(String xueqi) {
        this.xueqi = xueqi;
    }

    public String getXuenian() {
        return xuenian;
    }

    public void setXuenian(String xuenian) {
        this.xuenian = xuenian;
    }

    public String getStartTime() {
        return startTime;
    }

    public void setStartTime(String startTime) {
        this.startTime = startTime;
    }

    public String getEndTime() {
        return endTime;
    }

    public void setEndTime(String endTime) {
        this.endTime = endTime;
    }

    public int getMenshu() {
        return menshu;
    }

    public void setMenshu(int menshu) {
        this.menshu = menshu;
    }

    public String getIsReadDB() {
        return isReadDB;
    }

    public void setIsReadDB(String isReadDB) {
        this.isReadDB = isReadDB;
    }

}

public class Operate {
    /*
    * 取出文件內容，填充對象
    */
    public ElectSet findElectSet(String path){
       ElectSet electset=new ElectSet();
       String sets=ReadFile(path);//獲得json文件的內容
       JSONObject jo=JSONObject.fromObject(sets);//格式化成json對象
       //System.out.println("------------" jo);
       //String name = jo.getString("xuenian");
       //System.out.println(name);
       electset.setXueqi(jo.getString("xueqi"));
       electset.setXuenian(jo.getString("xuenian"));
       electset.setStartTime(jo.getString("startTime"));
       electset.setEndTime(jo.getString("endTime"));
       electset.setMenshu(jo.getInt("menshu"));
       electset.setIsReadDB(jo.getString("isReadDB"));
       return electset;
    }
    //設置屬性，并保存
    public boolean setElect(String path,String sets){
       try {
        writeFile(path,sets);
        return true;
       } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return false;
       }
    }
    //讀文件，返回字符串
    public String ReadFile(String path){
        File file = new File(path);
        BufferedReader reader = null;
        String laststr = "";
        try {
         //System.out.println("以行為單位讀取文件內容，一次讀一整行：");
         reader = new BufferedReader(new FileReader(file));
         String tempString = null;
         int line = 1;
         //一次讀入一行，直到讀入null為文件結束
         while ((tempString = reader.readLine()) != null) {
          //顯示行號
          System.out.println("line " + line + ": " + tempString);
          laststr = laststr + tempString;
          line ++;
         }
         reader.close();
        } catch (IOException e) {
         e.printStackTrace();
        } finally {
         if (reader != null) {
          try {
           reader.close();
          } catch (IOException e1) {
          }
         }
        }
        return laststr;
    }
             //把json格式的字符串寫到文件
    public void writeFile(String filePath, String sets) throws IOException {
        FileWriter fw = new FileWriter(filePath);
        PrintWriter out = new PrintWriter(fw);
        out.write(sets);
        out.println();
        fw.close();
        out.close();
       }
}

public class Use {
    // 取出json對象
    public void GetElectSettings(HttpServletRequest request,
            HttpServletResponse response) throws Exception {
        ElectSet electset = new ElectSet();
        String absPath = request.getRealPath("\\");
        String filePath = absPath + "public\\sets\\electSets.json";

        // 這里是調用，大家自己改改，我調用的業務層 的。
        electset = businessService.findElectSets(filePath);
        JSONArray jsonItems = new JSONArray();
        jsonItems.add(electset);
        JSONObject jo = new JSONObject();
        jo.put("data", jsonItems);
        System.out.println(jo);
        request.setCharacterEncoding("utf-8");
        response.setContentType("application/json;charset=utf-8");
        PrintWriter out = response.getWriter();
        out.print(jo);
    }

    // 修改json文件
    public void ChangeElectSet(HttpServletRequest request,
            HttpServletResponse response) throws Exception {
        request.setCharacterEncoding("UTF-8");
        response.setContentType("text/json;charset=utf-8");
//      log.info("reach ChangeElectSet");
        String json = (String) request.getParameter("json").trim();
//      log.info("Change ElectSet");
//      log.info(json);
        ElectSet sets = new ElectSet();
        JSONObject jsonObject = JSONObject.fromObject(json);
        sets = (ElectSet) JSONObject.toBean(jsonObject, ElectSet.class);
        if (sets.getIsReadDB() == "false") {
            sets.setIsReadDB("否");
        } else {
            sets.setIsReadDB("是");
        }
        String changes = "{\"xuenian\":\"";// 因為json的屬性要用引號，所以要用"轉義一下
        changes = sets.getXuenian() + "\",\"xueqi\":\"" + sets.getXueqi()
                + "\",\"startTime\":\"" + sets.getStartTime()
                + "\",\"endTime\":\"" + sets.getEndTime() + "\",\"menshu\":\""
                + sets.getMenshu() + "\",\"isReadDB\":\"" + sets.getIsReadDB()
                + "\"}";
        System.out.println(changes);
        String absPath = request.getRealPath("\\");
        String filePath = absPath + "public\\sets\\electSets.json";
    }
}