包含creat.json的词条

本文目录一览：

• 1、咨询一下数据库里通过SQL结构化查询出的表数据记录怎么转换为JSON格式？
• 2、json的赋值
• 3、Android 解析json问题
• 4、在eclipse中，如何导入json包和使用呢？
• 5、如何使用java创建json对象
• 6、Java解析json数据

咨询一下数据库里通过SQL结构化查询出的表数据记录怎么转换为JSON格式？

import java.io.StringWriter;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import org.codehaus.jackson.JsonFactory;

import org.codehaus.jackson.JsonGenerator;

import org.codehaus.jackson.JsonParser.Feature;

import org.codehaus.jackson.map.JsonSerializer;

import org.codehaus.jackson.map.ObjectMapper;

import org.codehaus.jackson.map.SerializationConfig.Feature;

import org.codehaus.jackson.type.TypeReference;

public class JsonUtils

{

private static ObjectMapper mapper = null;

static { mapper = new ObjectMapper();

mapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS, false);

mapper.configure(JsonParser.Feature.ALLOW_BACKSLASH_ESCAPING_ANY_CHARACTER, true);

}

public static String toJson(Object target)

{

String json = “”;

try {

StringWriter sw = new StringWriter();

JsonGenerator gen = new JsonFactory().createJsonGenerator(sw);

mapper.writeValue(gen, target);

gen.close();

json = sw.toString();

}

catch (Exception e) {

throw new UnexpectedException(“对象转换Json字符串出错,” + target.toString(), e);

}

return json;

}

}

json的赋值

function CreateJson(id,name) //JS 里面是不需要参数属性的

{

var jsonStr = {};

jsonStr.id = id;

jsonStr.name = name;

return jsonStr;

}

function UseJson()

{

var rows = []; //空JSON 数据集

for(var i=0;i变量;i++){

var id=你自己赋值;

var name=你自己赋值;

rows.push(CreateJson(id,name)); //往JSON 数据集中添加JSON 数据，原理类似 List

}

//结束后这里得到JSON数据集信息

alert(JSON.stringify(rows )); //将JSON 转化成string 输出，否则显示Object

//输出你想要的信息

}

以上纯手打！

Android 解析json问题

Android 解析json的方式为：

1、首先，搭建一个服务器的工程：JsonProject这个项目

源代码：

Person.java

package com.json.domain;

public class Person {

private int id;

private String name;

private String address;

public Person() {

super();

}

public Person(int id, String name, String addrss) {

super();

this.id = id;

this.name = name;

this.address = addrss;

}

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getAddress() {

return address;

}

public void setAddress(String address) {

this.address = address;

}

@Override

public String toString() {

return “Person [addrss=” + address + “, id=” + id + “, name=” + name

+ “]”;

}

}

JsonService.java

package com.json.service;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import com.json.domain.Person;

public class JsonService {

public JsonService() {

}

public Person getPerson(){

Person person = new Person(1001,”jack”,”上海黄浦区”);

return person;

}

public ListPerson getListPerson(){

ListPerson list = new ArrayListPerson();

Person person1 = new Person(1001,”jack”,”上海黄浦区”);

Person person2 = new Person(1002,”rose”,”上海闵行区”);

Person person3 = new Person(1003,”mick”,”上海黄浦区”);

list.add(person1);

list.add(person2);

list.add(person3);

return list;

}

public ListString getListString(){

ListString list = new ArrayListString();

list.add(“北京”);

list.add(“上海”);

list.add(“湖南”);

return list;

}

public ListMapString,Object getListMaps(){

ListMapString,Object list = new ArrayListMapString,Object();

MapString,Object map1 = new HashMapString, Object();

MapString,Object map2 = new HashMapString, Object();

map1.put(“id”, 1001);

map1.put(“name”, “jack”);

map1.put(“address”, “北京”);

map2.put(“id”, 1001);

map2.put(“name”, “rose”);

map2.put(“address”, “上海”);

list.add(map1);

list.add(map2);

return list;

}

}

JsonServlet.java

package com.json.servlet;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.json.service.JsonService;

import com.json.tools.JsonTools;

public class JsonServlet extends HttpServlet {

private JsonService service;

/**

* Constructor of the object.

*/

public JsonServlet() {

super();

}

/**

* Destruction of the servlet. br

*/

public void destroy() {

super.destroy(); // Just puts “destroy” string in log

// Put your code here

}

/**

* The doGet method of the servlet. br

*

* This method is called when a form has its tag value method equals to get.

*

* @param request the request send by the client to the server

* @param response the response send by the server to the client

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

*/

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

this.doPost(request, response);

}

/**

* The doPost method of the servlet. br

*

* This method is called when a form has its tag value method equals to post.

*

* @param request the request send by the client to the server

* @param response the response send by the server to the client

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

*/

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType(“text/html;charset=utf-8”);

request.setCharacterEncoding(“utf-8”);

response.setCharacterEncoding(“utf-8”);

PrintWriter out = response.getWriter();

String jsonString = “”;

String action_flag = request.getParameter(“action_flag”);

if(action_flag.equals(“person”)){

jsonString = JsonTools.createJsonString(“person”, service.getPerson());

}else if(action_flag.equals(“persons”)){

jsonString = JsonTools.createJsonString(“persons”, service.getListPerson());

}else if(action_flag.equals(“listString”)){

jsonString = JsonTools.createJsonString(“listString”, service.getListString());

}else if(action_flag.equals(“listMap”)){

jsonString = JsonTools.createJsonString(“listMap”, service.getListMaps());

}

out.println(jsonString);

out.flush();

out.close();

}

/**

* Initialization of the servlet. br

*

* @throws ServletException if an error occurs

*/

public void init() throws ServletException {

service = new JsonService();

}

}

2、通过浏览器

访问地址一：

输出以下结果：

{“person”:{“address”:”上海黄浦区”,”id”:1001,”name”:”jack”}

访问地址二：

输出以下结果：

{“persons”:[{“address”:”上海黄浦区”,”id”:1001,”name”:”jack”},{“addrss”:”上海闵行区”,”id”:1002,”name”:”rose”},{“address”:”上海黄浦区”,”id”:1003,”name”:”mick”}]}

访问地址三：

输出以下结果：

{“persons”:[“北京”,”上海”,”湖南”]}

访问地址四：

输出以下结果：

{“persons”:[{“id”:1001,”address”:”北京”,”name”:”jack”},{“id”:1001,”address”:”上海”,”name”:”rose”}]}

在eclipse中，如何导入json包和使用呢？

json-lib-2.3-jdk15.jar

commons-beanutils-1.7.0.jar

commons-httpclient-3.1.jar

commons-lang-2.3.jar

commons-logging-1.0.4.jar

commons-collections-3.1.jar

ezmorph-1.0.3.jar

这些包可以从一下地方下载：

如果不关联这些包，则会出现以下错误：

java.lang.NoClassDefFoundError: net/sf/ezmorph/Morpher

java.lang.NoClassDefFoundError: org/apache/commons/collections/map/ListOrderedMap

java.lang.NoClassDefFoundError: org/apache/commons/beanutils/DynaBean

java.lang.NoClassDefFoundError: org/apache/commons/codec/DecoderException

java.lang.NoClassDefFoundError: org/apache/commons/lang/exception/NestableRuntimeException

java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory

使用的话

JSON Editor Plugin 是 Eclipse 下用来编辑 JSON 格式数据的插件，具有语法着色、文档结构概览、显示格式化等功能。

如何使用java创建json对象

//将数据转换为Json 

public static String createJsonString(String key, Object value) {  

    JSONObject jsonObject = new JSONObject();  

    jsonObject.put(key, value); 

    return jsonObject.toString();

}

Java解析json数据

一、 JSON （JavaScript Object Notation）一种简单的数据格式，比xml更轻巧。

Json建构于两种结构：

1、“名称/值”对的集合（A collection of name/value pairs）。不同的语言中，它被理解为对象（object），纪录（record），结构（struct），字典（dictionary），哈希表（hash table），有键列表（keyed list），或者关联数组 （associative array）。 如：

{

“name”:”jackson”,

“age”:100

}

2、值的有序列表（An ordered list of values）。在大部分语言中，它被理解为数组（array）如：

{

“students”:

[

{“name”:”jackson”,“age”:100},

{“name”:”michael”,”age”:51}

]

}

二、java解析JSON步骤

A、服务器端将数据转换成json字符串

首先、服务器端项目要导入json的jar包和json所依赖的jar包至builtPath路径下（这些可以到JSON-lib官网下载：）

然后将数据转为json字符串，核心函数是：

public static String createJsonString(String key, Object value)

{

JSONObject jsonObject = new JSONObject();

jsonObject.put(key, value);

return jsonObject.toString();

}

B、客户端将json字符串转换为相应的javaBean

1、客户端获取json字符串（因为android项目中已经集成了json的jar包所以这里无需导入）

public class HttpUtil

{

public static String getJsonContent(String urlStr)

{

try

{// 获取HttpURLConnection连接对象

URL url = new URL(urlStr);

HttpURLConnection httpConn = (HttpURLConnection) url

.openConnection();

// 设置连接属性

httpConn.setConnectTimeout(3000);

httpConn.setDoInput(true);

httpConn.setRequestMethod(“GET”);

// 获取相应码

int respCode = httpConn.getResponseCode();

if (respCode == 200)

{

return ConvertStream2Json(httpConn.getInputStream());

}

}

catch (MalformedURLException e)

{

// TODO Auto-generated catch block

e.printStackTrace();

}

catch (IOException e)

{

// TODO Auto-generated catch block

e.printStackTrace();

}

return “”;

}

private static String ConvertStream2Json(InputStream inputStream)

{

String jsonStr = “”;

// ByteArrayOutputStream相当于内存输出流

ByteArrayOutputStream out = new ByteArrayOutputStream();

byte[] buffer = new byte[1024];

int len = 0;

// 将输入流转移到内存输出流中

try

{

while ((len = inputStream.read(buffer, 0, buffer.length)) != -1)

{

out.write(buffer, 0, len);

}

// 将内存流转换为字符串

jsonStr = new String(out.toByteArray());

}

catch (IOException e)

{

// TODO Auto-generated catch block

e.printStackTrace();

}

return jsonStr;

}

}

2、获取javaBean

public static Person getPerson(String jsonStr)

{

Person person = new Person();

try

{// 将json字符串转换为json对象

JSONObject jsonObj = new JSONObject(jsonStr);

// 得到指定json key对象的value对象

JSONObject personObj = jsonObj.getJSONObject(“person”);

// 获取之对象的所有属性

person.setId(personObj.getInt(“id”));

person.setName(personObj.getString(“name”));

person.setAddress(personObj.getString(“address”));

}

catch (JSONException e)

{

// TODO Auto-generated catch block

e.printStackTrace();

}

return person;

}

public static ListPerson getPersons(String jsonStr)

{

ListPerson list = new ArrayListPerson();

JSONObject jsonObj;

try

{// 将json字符串转换为json对象

jsonObj = new JSONObject(jsonStr);

// 得到指定json key对象的value对象

JSONArray personList = jsonObj.getJSONArray(“persons”);

// 遍历jsonArray

for (int i = 0; i personList.length(); i++)

{

// 获取每一个json对象

JSONObject jsonItem = personList.getJSONObject(i);

// 获取每一个json对象的值

Person person = new Person();

person.setId(jsonItem.getInt(“id”));

person.setName(jsonItem.getString(“name”));

person.setAddress(jsonItem.getString(“address”));

list.add(person);

}

}

catch (JSONException e)

{

// TODO Auto-generated catch block

e.printStackTrace();

}

return list;

}