如何打印从控制器类返回到jsp页面的JSON数组 [英] How to Print JSON Array returned from controller class to jsp page

问题描述

我从java类返回一个json数组作为返回类型，并试图在jsp页面上显示数据.一切正常(如调试所述).但是不知道jsp/html页面的方法(代码/语法). 课程

i am returning a json array from java class as return type and trying to display data on jsp page. everything is ok (as debugging says). But dont know the method (code/syntax) for jsp/html page. class

JSONArray jsonArray = new JSONArray();

    public JSONArray get_user() {

        String sql = "SELECT * FROM USER_INFO";
        try {
            con = new connection.connect().getConnection();
            smt = con.createStatement();
            rset = smt.executeQuery(sql);

            while (rset.next()) {
                JSONObject obj = new JSONObject();
                obj.put("Email", rset.getString(2));
                obj.put("Password", rset.getString(3));
                jsonArray.put(obj);
            }
        } catch (Exception ex) {
            ex.getMessage();
        }

        return jsonArray;
    }

jsp

<%
controller.fetch_user obj = new controller.fetch_user();
obj.get_user();
%>
<table>
<tr><td>Email</td><td>Password</td></tr>

 *** here i want to display all the records ****

</table>

推荐答案

在返回json的最佳解决方案中，您可以返回pojo

best solution for it instate of returning a json you can return pojo

创建喜欢的人

class UserInfo{
 private String email;
 private String Password;
 //setter and getter
}

然后翻阅userInfo列表

and then reurn a list of userInfo

所以您的方法将是

public List<UserInfo> get_user() {
    List<UserInfo> userInfoList = new AraayList<UserInfo>()
    String sql = "SELECT * FROM USER_INFO";
    try {
        con = new connection.connect().getConnection();
        smt = con.createStatement();
        rset = smt.executeQuery(sql);

        while (rset.next()) {
            UserInfo obj = new UserInfo();
            obj.setEmail(rset.getString(2))
            obj.setPassword(rset.getString(3))

            userInfoList.add(obj);
        }
    } catch (Exception ex) {
        ex.getMessage();
    }

    return userInfoList;
}
// for json object

JSONArray jsonArray = new JSONArray();

public JSONArray get_user() {

    String sql = "SELECT * FROM USER_INFO";
    try {
        con = new connection.connect().getConnection();
        smt = con.createStatement();
        rset = smt.executeQuery(sql);

        while (rset.next()) {
            JSONObject obj = new JSONObject();
            obj.put("Email", rset.getString(2));
            obj.put("Password", rset.getString(3));
            jsonArray.put(obj);
        }
    } catch (Exception ex) {
        ex.getMessage();
    }

    return jsonArray;
}

您的jsp代码是

<%
 controller.fetch_user obj = new controller.fetch_user();
 obj.get_user();
%>
<table>
<tr><td>Email</td><td>Password</td></tr>
for(UserInfo userInfo:obj){
<%
%>
<tr>
  <td><%=userInfo.getEmail()%><td>
  <td><%=userInfo.getPassword()%><td>
</tr> 
<%
 }
%>

</table>

，如果您的方法仍返回jsonAraay，则代码将为

and if your method still return jsonAraay the code will be

 <%
 controller.fetch_user obj = new controller.fetch_user();
JSONArray getArray = obj.get_user();
%>
<table>
<tr><td>Email</td><td>Password</td></tr>



<%
  for(int i = 0; i < getArray.size(); i++){
  JSONObject userInfo = getArray.getJSONObject(i);
%>
<tr>
  <td><%=userInfo.get("Email")%><td>
  <td><%=userInfo.get("Password")%><td>
</tr> 
<%
 }
%>

</table>

在jsp代码中，您可以像在Java中一样访问它

and in jsp code you can access this like in java you are access it

也许会对您有很大帮助

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