JSON数据交互实例-优快云博客

Json的使用

1　找到json.js文件和json.jar文件，其中json是用页面上构建json值串的方法库，json.jar是java解析json值串的类库。（串值有

二种,1名值对，2有序列表）

2 测试页面
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>JSON Example</title>

var xmlHttp;

function parseResults() {
    var responseDiv = document.getElementById("serverResponse");
    if(responseDiv.hasChildNodes()) {
        responseDiv.removeChild(responseDiv.childNodes[0]);
    }

    var responseText = document.createTextNode(xmlHttp.responseText);
    responseDiv.appendChild(responseText);
}

function getCarObject() {
return new Car("Dodge", "Coronet R/T", 1968, "yellow");
}

function Car(make, model, year, color) {
    this.make = make;
    this.model = model;
    this.year = year;
    this.color = color;
}

</script>
</head>

<body>

<br/><br/>
<form action="#">
<input type="button" value="Click here to send JSON data to the server"
onclick="doJSON();"/>
</form>

<h2>Server Response:</h2>

</body>
</html>

3 测试类

package ajaxbook.chap3;

import java.io.BufferedReader;
import java.io.IOException;
import java.text.ParseException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.json.JSONObject;

public class JSONExample extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        String json = readJSONStringFromRequestBody(request);

        //Use the JSON-Java binding library to create a JSON object in Java
        JSONObject jsonObject = null;
        try {
            jsonObject = new JSONObject(json);
        }
        catch(ParseException pe) {
            System.out.println("ParseException: " + pe.toString());
        }

        String responseText = "You have a " + jsonObject.getInt("year") + " "
            + jsonObject.getString("make") + " " + jsonObject.getString("model")
            + " " + " that is " + jsonObject.getString("color") + " in color.";

        response.setContentType("text/xml");
        response.getWriter().print(responseText);
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
      doPost(request,response);
    }

    private String readJSONStringFromRequestBody(HttpServletRequest request){
        StringBuffer json = new StringBuffer();
        String line = null;
        try {
            BufferedReader reader = request.getReader();
            while((line = reader.readLine()) != null) {
                json.append(line);
            }
        }
        catch(Exception e) {
            System.out.println("Error reading JSON string: " + e.toString());
        }
        return json.toString();
    }
}

4 json.js

var JSON = {
    org: 'http://www.JSON.org',
    copyright: '(c)2005 JSON.org',
    license: 'http://www.crockford.com/JSON/license.html',
    stringify: function stringify(arg) {
        var c, i, l, s = '', v;

        switch (typeof arg) {
        case 'object':
            if (arg) {
                if (arg.constructor == Array) {
                    for (i = 0; i < arg.length; ++i) {
                        v = this.stringify(arg[i]);
                        if (s) {
                            s += ',';
                        }
                        s += v;
                    }
                    return '[' + s + ']';
                } else if (typeof arg.toString != 'undefined') {
                    for (i in arg) {
                        v = arg[i];
                        if (typeof v != 'undefined' && typeof v != 'function') {
                            v = this.stringify(v);
                            if (s) {
                                s += ',';
                            }
                            s += this.stringify(i) + ':' + v;
                        }
                    }
                    return '{' + s + '}';
                }
            }
            return 'null';
        case 'number':
            return isFinite(arg) ? String(arg) : 'null';
        case 'string':
            l = arg.length;
            s = '"';
            for (i = 0; i < l; i += 1) {
                c = arg.charAt(i);
                if (c >= ' ') {
                    if (c == '//' || c == '"') {
                        s += '//';
                    }
                    s += c;
                } else {
                    switch (c) {
                        case '/b':
                            s += '//b';
                            break;
                        case '/f':
                            s += '//f';
                            break;
                        case '/n':
                            s += '//n';
                            break;
                        case '/r':
                            s += '//r';
                            break;
                        case '/t':
                            s += '//t';
                            break;
                        default:
                            c = c.charCodeAt();
                            s += '//u00' + Math.floor(c / 16).toString(16) +
                                (c % 16).toString(16);
                    }
                }
            }
            return s + '"';
        case 'boolean':
            return String(arg);
        default:
            return 'null';
        }
    },
    parse: function (text) {
        var at = 0;
        var ch = ' ';

        function error(m) {
            throw {
                name: 'JSONError',
                message: m,
                at: at - 1,
                text: text
            };
        }

        function next() {
            ch = text.charAt(at);
            at += 1;
            return ch;
        }

function string() {
var i, s = '', t, u;

            if (ch == '"') {
outer:          while (next()) {
                    if (ch == '"') {
                        next();
                        return s;
                    } else if (ch == '//') {
                        switch (next()) {
                        case 'b':
                            s += '/b';
                            break;
                        case 'f':
                            s += '/f';
                            break;
                        case 'n':
                            s += '/n';
                            break;
                        case 'r':
                            s += '/r';
                            break;
                        case 't':
                            s += '/t';
                            break;
                        case 'u':
                            u = 0;
                            for (i = 0; i < 4; i += 1) {
                                t = parseInt(next(), 16);
                                if (!isFinite(t)) {
                                    break outer;
                                }
                                u = u * 16 + t;
                            }
                            s += String.fromCharCode(u);
                            break;
                        default:
                            s += ch;
                        }
                    } else {
                        s += ch;
                    }
                }
            }
            error("Bad string");
        }

function array() {
var a = [];

            if (ch == '[') {
                next();
                white();
                if (ch == ']') {
                    next();
                    return a;
                }
                while (ch) {
                    a.push(value());
                    white();
                    if (ch == ']') {
                        next();
                        return a;
                    } else if (ch != ',') {
                        break;
                    }
                    next();
                    white();
                }
            }
            error("Bad array");
        }

function object() {
var k, o = {};

            if (ch == '{') {
                next();
                white();
                if (ch == '}') {
                    next();
                    return o;
                }
                while (ch) {
                    k = string();
                    white();
                    if (ch != ':') {
                        break;
                    }
                    next();
                    o[k] = value();
                    white();
                    if (ch == '}') {
                        next();
                        return o;
                    } else if (ch != ',') {
                        break;
                    }
                    next();
                    white();
                }
            }
            error("Bad object");
        }

function number() {
var n = '', v;

            if (ch == '-') {
                n = '-';
                next();
            }
            while (ch >= '0' && ch <= '9') {
                n += ch;
                next();
            }
            if (ch == '.') {
                n += '.';
                while (next() && ch >= '0' && ch <= '9') {
                    n += ch;
                }
            }
            v = +n;
            if (!isFinite(v)) {
                error("Bad number");
            } else {
                return v;
            }
        }

        function value() {
            white();
            switch (ch) {
                case '{':
                    return object();
                case '[':
                    return array();
                case '"':
                    return string();
                case '-':
                    return number();
                default:
                    return ch >= '0' && ch <= '9' ? number() : word();
            }
        }

return value();
}
};