Android 使用Json实现服务器与客户端数据的交互
发布日期：2021-06-30 22:34:53
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第一步：写一个远程查询工具类，使用单例模式
/** * 查询远程服务器的工具 * @author chen.lin * */public class QueryUtils { //private static final String TAG = "CommonUtils"; private static QueryUtils instance; private SharedPreferences sp; private QueryUtils(Context context){ sp = context.getSharedPreferences(Constant.CONFIG, Context.MODE_PRIVATE); } public static QueryUtils getInstance(Context context){ if (instance == null) { synchronized (QueryUtils.class) { if (instance == null) { instance = new QueryUtils(context); } } } return instance; }/** * 请求服务器得到返回值 * * @param keyword * @return * @throws Exception */ public String queryServer(String keyword, String reqType, String servlet) throws Exception { String returnValue = null; // 使用Map封装请求参数 Map map = new HashMap (); map.put("reqType", reqType); map.put("localIP", sp.getString(Constant.NETIP, "")); if (!TextUtils.isEmpty(keyword)) { map.put("keyword", keyword); } String url = "http://" + sp.getString(Constant.NETURL, "") + "/ymerp/" + servlet; returnValue = postRequest(url, map); return returnValue; }} /** * 请求远程服务器，并封装参数信息 * @param url * @param rawParams * @return * @throws Exception */ public static String postRequest(String url, Map rawParams) throws Exception { // 创建HttpPost对象。 HttpPost post = new HttpPost(url); // 如果传递参数个数比较多的话可以对传递的参数进行封装 List params = new ArrayList (); for (String key : rawParams.keySet()) { // 封装请求参数 params.add(new BasicNameValuePair(key, rawParams.get(key))); } //Logger.i(TAG, "params------------------->" + params); // 设置请求参数 post.setEntity(new UrlEncodedFormEntity(params, "UTF-8")); HttpParams httpParameters = new BasicHttpParams(); HttpConnectionParams.setConnectionTimeout(httpParameters, 3000); HttpConnectionParams.setSoTimeout(httpParameters, 15000); DefaultHttpClient httpClient = new DefaultHttpClient(httpParameters); // 发送POST请求 HttpResponse httpResponse = httpClient.execute(post); // 如果服务器成功地返回响应 String result = null; if (httpResponse.getStatusLine().getStatusCode() == 200) { // 获取服务器响应字符串 result = EntityUtils.toString(httpResponse.getEntity(), "UTF-8"); Logger.i(TAG, "result-------->" + result); } return result; } 第二步：使用软引用把远程得到的数据缓存到手机，如果服务器有数据更新，重新查询
/** * 使用这个需要注意，一切都必须与服务器上的字段一一对应，大小写一致 为了保持一致，所有的实体都必须小写,远程数据库上的字段也得小写 * * @author chen.lin * */@SuppressWarnings({ "unchecked", "deprecation" })public class BaseManager { private static BaseManager instance; private QueryUtils queryUtils; private SharedPreferences sp; private Context context; private BaseManager(Context context) { this.context = context; queryUtils = QueryUtils.getInstance(context); sp = context.getSharedPreferences(Constant.CONFIG, Context.MODE_PRIVATE); } public static BaseManager getInstance(Context context) { if (instance == null){ synchronized (BaseManager.class) { if (instance == null) { instance = new BaseManager(context); } } } return instance; } private static Map > LISTCACHE;// static { // 16M，如果不足<16M(模拟器) // 32M，真机 if (MemoryManager.hasAcailMemory()) { LISTCACHE = new HashMap >(); } else { LISTCACHE = new SoftMap >(); } } private static Map DOCCACHE;// static { // 16M，如果不足<16M(模拟器) // 32M，真机 if (MemoryManager.hasAcailMemory()) { DOCCACHE = new HashMap (); } else { DOCCACHE = new SoftMap (); } }public List queryListByCache(Class clazz, String key, String reqType, String servlet) throws Exception { List list = null; // 一旦创建过，重用 // 判断是否创建了——曾经创建过的界面需要存储 if (LISTCACHE != null && LISTCACHE.containsKey(key)) { // 创建了，重用 list = (List ) LISTCACHE.get(key); if (list == null || list.isEmpty()) { // 有时候查询 的数据过大，viewcache中放置不了那么多数据，就会被垃圾回收站回收，得重新查询远程数据库 list = getListFromServer(clazz, key, reqType, servlet); LISTCACHE.put(key, list); } } else { // 否则，创建 list = getListFromServer(clazz, key, reqType, servlet); LISTCACHE.put(key, list); } return list; } public List getListFromServer(Class clazz, String keyword, String reqType, String servlet) throws Exception { List list = new ArrayList (); String returnValue = queryUtils.queryServer(keyword, reqType, servlet); if (!TextUtils.isEmpty(returnValue)) { Gson gson = new Gson(); JsonParser jsonParser = new JsonParser(); JsonArray jsonArray = jsonParser.parse(returnValue).getAsJsonArray(); if (jsonArray != null) { T t = null; // 循环记录数（多少条） for (JsonElement json : jsonArray) { if (json != null) { t = gson.fromJson(json, clazz); list.add(t); } } } } return list; } public T queryDocByCache(Class clazz, String key, String reqType, String servlet) throws Exception { T t = null; // 一旦创建过，重用 // 判断是否创建了——曾经创建过的界面需要存储 if (DOCCACHE != null && DOCCACHE.containsKey(key)) { // 创建了，重用 t = (T) DOCCACHE.get(key); if (t == null) { // 有时候查询 的数据过大，viewcache中放置不了那么多数据，就会被垃圾回收站回收，得重新查询远程数据库 t = getDocFromServer(clazz, key, reqType, servlet); DOCCACHE.put(key, t); } } else { // 否则，创建 t = getDocFromServer(clazz, key, reqType, servlet); DOCCACHE.put(key, t); } return t; } public T getDocFromServer(Class clazz, String keyword, String reqType, String servlet) throws Exception { String returnValue = queryUtils.queryServer(keyword, reqType, servlet); if (!TextUtils.isEmpty(returnValue)) { Gson gson = new Gson(); T t = gson.fromJson(returnValue, clazz); return t; } return null; } /** * 查询判断客户是否已经添加 * * @param keyword * @param dialog * @return * @throws Exception */ public boolean isAccountExist(String keyword) throws Exception { String returnValue = queryUtils.queryServer(keyword, "queryaccountExist", "AccountDocumentServlet"); if (!TextUtils.isEmpty(returnValue) && "true".equals(returnValue.trim())) { return true; } return false; } /** * 更新服务器上的数据 * @param context * @param params * @param servlet * @return * @throws Exception */ public void updateServer(final RequestParams params, String servlet) { AsyncHttpClient client = new AsyncHttpClient(); String url = "http://" + sp.getString(Constant.NETURL, "") + "/ymerp/" + servlet; client.post(url, params, new AsyncHttpResponseHandler() { @Override public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) { try { String returnValue = new String(responseBody); JSONObject jsonObject = new JSONObject(returnValue); if ("success".equalsIgnoreCase(jsonObject.getString("result"))) { if (params.has("sendread")) { Logger.i("update", "更新成功！"); }else { Toast.makeText(context, "更新成功！", Toast.LENGTH_SHORT).show(); } }else { if (params.has("sendread")) { Logger.i("update", "更新失败！"); }else { Toast.makeText(context, "更新失败！", Toast.LENGTH_SHORT).show(); } } } catch (JSONException e) { e.printStackTrace(); Toast.makeText(context, "json格式数据有误！", Toast.LENGTH_SHORT).show(); } } @Override public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) { Toast.makeText(context, "网络错误！错误信息：" + error.getMessage(), Toast.LENGTH_SHORT).show(); } }); }} 第三步：使用事例-客户信息查询
public class SearchActivity extends CommonActivity implements OnClickListener { private BaseManager mManager;private ListView mListView ;private Button mBtnQuery;private QueryAccountAdapter mAdapter;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.search);// 初始化组件initView();// 进出动画效果overridePendingTransition(R.anim.push_bottom_in, R.anim.push_bottom_out);}}private void initView() {mManager = BaseManager.getInstance(this);mListView = (ListView) findViewById(R.id.lv_search);mButton = (Button)findViewById(R.id.bt_query);mButton.setOnClickListener(this);mAdapter = new QueryAccountAdapter(this, mAccounts);mListView.setAdapter(mAdapter);}@Overridepublic void onClick(View v) {if(v == mBtnQuery){mAccounts = mManager.getListFromServer(Account.class, query, "queryAccountByKey", "QueryServlet");}}} 客户实体类：
/** * 客户信息 * * @author chen.lin * @createtime 20150217 */public class Account implements Serializable { /** * */ private static final long serialVersionUID = 1L; private String id; private String sname;// 客户名称 private String scode;// 客户编码 private String contact;// 联系人 private String idcontact;// 联系人id private String emtype;// 客户分类 private String xsly;// 客户来源 private String xsbh;// 线索编号 private String xs;// 线索名称 private String idlead;// 线索id private String leadscode; private String idzh;// 相关展会 private String srcpath;// 来源途径 private String emindustry;// 行业 private String idarea; // 行政区域 private String saddress;// 客户地址 private String shdz;// 收货地址 private String cclx;// 乘车路线 private String spostcode;// 邮编 private String stel;// 手机 private String telcode;// 电话号码 private String sfax;// 传真 private String semail;// 邮箱 private String swebsite;// 站点主页 private String iddep;// 负责人部门 private String idowner;// 负责人 private String created;// 新建时间 private String createdby;// 新建人 private String updated;// 编辑时间 private String updatedby;// 编辑人 public String getIdcontact() { return idcontact; } public void setIdcontact(String idcontact) { this.idcontact = idcontact; } public String getContact() { return contact; } public void setContact(String contact) { this.contact = contact; } public String getIdlead() { return idlead; } public void setIdlead(String idlead) { this.idlead = idlead; } public String getLeadscode() { return leadscode; } public void setLeadscode(String leadscode) { this.leadscode = leadscode; } public String getTelcode() { return telcode; } public void setTelcode(String telcode) { this.telcode = telcode; } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getSname() { return sname; } public void setSname(String sname) { this.sname = sname; } public String getScode() { return scode; } public void setScode(String scode) { this.scode = scode; } public String getEmtype() { return emtype; } public void setEmtype(String emtype) { this.emtype = emtype; } public String getXsly() { return xsly; } public void setXsly(String xsly) { this.xsly = xsly; } public String getXsbh() { return xsbh; } public void setXsbh(String xsbh) { this.xsbh = xsbh; } public String getXs() { return xs; } public void setXs(String xs) { this.xs = xs; } public String getIdzh() { return idzh; } public void setIdzh(String idzh) { this.idzh = idzh; } public String getSrcpath() { return srcpath; } public void setSrcpath(String srcpath) { this.srcpath = srcpath; } public String getEmindustry() { return emindustry; } public void setEmindustry(String emindustry) { this.emindustry = emindustry; } public String getIdarea() { return idarea; } public void setIdarea(String idarea) { this.idarea = idarea; } public String getSaddress() { return saddress; } public void setSaddress(String saddress) { this.saddress = saddress; } public String getShdz() { return shdz; } public void setShdz(String shdz) { this.shdz = shdz; } public String getCclx() { return cclx; } public void setCclx(String cclx) { this.cclx = cclx; } public String getSpostcode() { return spostcode; } public void setSpostcode(String spostcode) { this.spostcode = spostcode; } public String getStel() { return stel; } public void setStel(String stel) { this.stel = stel; } public String getSfax() { return sfax; } public void setSfax(String sfax) { this.sfax = sfax; } public String getSemail() { return semail; } public void setSemail(String semail) { this.semail = semail; } public String getSwebsite() { return swebsite; } public void setSwebsite(String swebsite) { this.swebsite = swebsite; } public String getIddep() { return iddep; } public void setIddep(String iddep) { this.iddep = iddep; } public String getIdowner() { return idowner; } public void setIdowner(String idowner) { this.idowner = idowner; } public String getCreated() { return created; } public void setCreated(String created) { this.created = created; } public String getCreatedby() { return createdby; } public void setCreatedby(String createdby) { this.createdby = createdby; } public String getUpdated() { return updated; } public void setUpdated(String updated) { this.updated = updated; } public String getUpdatedby() { return updatedby; } public void setUpdatedby(String updatedby) { this.updatedby = updatedby; } public Account(String id, String sname, String scode, String idowner) { this.id = id; this.sname = sname; this.scode = scode; this.idowner = idowner; } public Account(String id, String sname, String scode, String emtype, String xsly, String xsbh, String xs, String idzh, String srcpath, String emindustry, String idarea, String saddress, String shdz, String cclx, String spostcode, String stel, String sfax, String semail, String swebsite, String iddep, String idowner, String created, String createdby, String updated, String updatedby) { this.id = id; this.sname = sname; this.scode = scode; this.emtype = emtype; this.xsly = xsly; this.xsbh = xsbh; this.xs = xs; this.idzh = idzh; this.srcpath = srcpath; this.emindustry = emindustry; this.idarea = idarea; this.saddress = saddress; this.shdz = shdz; this.cclx = cclx; this.spostcode = spostcode; this.stel = stel; this.sfax = sfax; this.semail = semail; this.swebsite = swebsite; this.iddep = iddep; this.idowner = idowner; this.created = created; this.createdby = createdby; this.updated = updated; this.updatedby = updatedby; } public Account() { super(); }} 第四步：服务器端 queryAccountByKey就是从客户端传过来的值
/** * * @author chen.lin */public class QueryServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8"); response.setCharacterEncoding("UTF-8"); request.setCharacterEncoding("UTF-8"); PrintWriter out = response.getWriter(); String reqType = request.getParameter("reqType"); String localIP = request.getParameter("localIP"); EJBClientLocal.setServerip(localIP); /** * 根据关键字查询服务单 */ if (reqType != null && "queryAccountByKey".equalsIgnoreCase(reqType)) { // 根据查询关键字查找对应用户列表 String keyword = request.getParameter("keyword"); System.out.println("keyword ----------------------:" + keyword); try { List list = EJBClientLocal.getMetaCRMIntegratedSessionBeanLocal().queryAccountByKey(keyword); System.out.println(" queryAccountByKey list:" + list); if (list != null) { JSONArray json = JSONArray.fromObject(list); // 输出响应 out.println(json.toString()); out.flush(); } } catch (Exception ex) { System.out.println("queryAccountByKey error:" + ex.getMessage()); } } } @Override public String getServletInfo() { return "Short description"; }} 第五步：查询数据库
@Statelesspublic class MetaCRMIntegratedSessionBean implements MetaCRMIntegratedSessionBeanRemote, MetaCRMIntegratedSessionBeanLocal { @Resource SessionContext ctx; @PersistenceContext(unitName = "meta_crm_ejbPU") private EntityManager em; private DBMSqlServer2005 dbm = null; private Statement statement = null; private PreparedStatement pStatement = null; SimpleDateFormat yyyymmdd = new SimpleDateFormat("yyyy-MM-dd"); @AroundInvoke public Object log(InvocationContext ctx) throws Exception { String className = ctx.getTarget().getClass().getName(); String mothodName = ctx.getMethod().getName(); String target = className + "." + mothodName + "()"; System.out.println("开始调用 " + target + "方法"); long start = System.currentTimeMillis(); try { Object localObject1 = ctx.proceed(); long time; return localObject1; } catch (Exception e) { return null; } finally { long time = System.currentTimeMillis() - start; System.out.print(target + "方法执行完毕用时 " + time + " ms"); } } /** * 查询客户信息 * @param keyword * @return */ public List queryAccountByKey(String keyword) { List list = new ArrayList (); String sql = "select acc.id, acc.sname, acc.scode, " + " con.sname as contact , emp1.sname as createdby, acc.created, acc.saddress, con.id " + " from account acc " + " left join org_employee emp1 on emp1.id = acc.createdby "//申请人名称 + " left join contact con on acc.id=con.idaccount "//联系人 + " where 1=1 "; if (keyword != null) { System.out.println("keyword----------------------->" + keyword); sql += " and acc.sname like '%" + keyword + "%'"; sql += " or emp1.sname like '%" + keyword + "%'"; } sql += " order by acc.created desc"; System.out.println("sql----------------------->" + sql); Connection conn = getConn(); ResultSet rs = null; Statement st = null; try { st = conn.createStatement(); rs = st.executeQuery(sql); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss"); while (rs.next()) { JSONObject jsonObject = new JSONObject(); jsonObject.put("id", rs.getObject(1) != null ? rs.getObject(1) : ""); jsonObject.put("sname", rs.getObject(2) != null ? rs.getObject(2) : ""); jsonObject.put("scode", rs.getObject(3) != null ? rs.getObject(3) : ""); jsonObject.put("contact", rs.getObject(4) != null ? rs.getObject(4) : ""); jsonObject.put("createdby", rs.getObject(5) != null ? rs.getObject(5) : ""); setTime(rs, sdf, jsonObject, "created", 6); jsonObject.put("saddress", rs.getObject(7) != null ? rs.getObject(7) : ""); jsonObject.put("idcontact", rs.getObject(8) != null ? rs.getObject(8) : ""); list.add(jsonObject); } } catch (SQLException ex) { ex.printStackTrace(); } finally { dbm.closeConn(); } return list; } } ———————————————————————
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