首先是安卓端，我主要上传一个User对象，下面是安卓端的代码通过okhttp3，gson编译成json格式上传

需要引用

compile 'com.google.code.gson:gson:2.8.1'

下面是客户端的一个功能的代码，主要将对象User上传给服务器，其中通过bundle将返回的对象传入到别的activity。本来想删除的，但是对于初学者应该还是很实用，gson.toJson（）这个方法就是将user对象编译成json格式的字符串，方便上传给服务器

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/** * 发送post请求 */ public User user = new User(); public void postRequest(){ OkHttpClient client = new OkHttpClient(); user.setUsername(username.getText().toString()); user.setPassword(content.getText().toString()); Gson gson = new Gson(); //使用Gson将对象转换为json字符串 String json = gson.toJson(user); RequestBody requestBody = FormBody.create(MediaType.parse("application/json; charset=utf-8") , json); Request request = new Request.Builder() .url(httpURL+"/HttpWeb/LoginServlet")//请求的url .post(requestBody) .build(); Call call = client.newCall(request); call.enqueue(new Callback() { @Override public void onFailure(Call call, IOException e) { } @Override public void onResponse(Call call, Response response) throws IOException { final String res = response.body().string(); runOnUiThread(new Runnable() { @Override public void run() { resultTV.setText(res); Log.v("Main.ID=",res); if (!res.equals(null)){ Toast.makeText(Main.this,"登陆成功",Toast.LENGTH_SHORT).show(); user.setId(res); Intent intent = new Intent(); intent.setClass(Main.this,MainActivity.class);//跳转到加载界面 Bundle bundle = new Bundle(); bundle.putParcelable("user", user); intent.putExtras(bundle); startActivity(intent); }else{ Toast.makeText(Main.this,"登陆失败",Toast.LENGTH_SHORT).show(); } } }); } }); }

User表，其中实现接口Parcelable是为了让bundle可以传递这个对象，使用bundle.putParcelable()这个办法

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import android.os.Parcel; import android.os.Parcelable; import java.io.Serializable; /** * Created by acer1 on 2018/4/5. */ public class User implements Parcelable,Serializable{ private String id; private String username; private String password; private String Nickname; private String Individuality_signature; public User(Parcel in) { id = in.readString(); username = in.readString(); password = in.readString(); } public static final Creator<User> CREATOR = new Creator<User>() { @Override public User createFromParcel(Parcel in) { return new User(in); } @Override public User[] newArray(int size) { return new User[size]; } }; public User() { } public String getNickname() { return Nickname; } public void setNickname(String nickname) { Nickname = nickname; } public String getIndividuality_signature() { return Individuality_signature; } public void setIndividuality_signature(String individuality_signature) { Individuality_signature = individuality_signature; } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } @Override public int describeContents() { return 0; } @Override public void writeToParcel(Parcel dest, int flags) { dest.writeString(id); dest.writeString(username); dest.writeString(password); } }

现在客户端基本就完事了，下面是服务器的代码，我开始学的时候就主要想学怎么接收json格式的数据，我相信大家也是想学怎么接收json数据格式的数据，通过gson将接收的数据解析成对象，看代码。我们还要在服务器里面写一个javabean，让json数据映射成这个javabean,方便提取数据

首先我们导入一些包，让我们可以接收到json数据

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protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("application/json"); response.setCharacterEncoding("UTF-8"); request.setCharacterEncoding("UTF-8"); /** * 接收json */ BufferedReader reader = request.getReader(); String json = reader.readLine(); System.out.println(json); Gson gson =new Gson(); User user = gson.fromJson(json, User.class); System.out.println(user.getUsername()); System.out.println(user.getPassword()); PrintWriter out = response.getWriter(); Integer msg; try { msg = UserDao.selectUser(user); out.print(msg); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } reader.close(); }

其中提取json数据和解析的代码就是下面这段代码

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response.setContentType("application/json"); response.setCharacterEncoding("UTF-8"); request.setCharacterEncoding("UTF-8"); /** * 接收json */ BufferedReader reader = request.getReader(); String json = reader.readLine(); System.out.println(json); Gson gson =new Gson(); User user = gson.fromJson(json, User.class); System.out.println(user.getUsername()); System.out.println(user.getPassword());

然后就是服务器端的javabean

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public class User { private String id; private String username; private String password; private String Nickname; private String Individuality_signature; public String getNickname() { return Nickname; } public void setNickname(String nickname) { Nickname = nickname; } public String getIndividuality_signature() { return Individuality_signature; } public void setIndividuality_signature(String individuality_signature) { Individuality_signature = individuality_signature; } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }

到这里基本的过程就结束了，从安卓端上传json数据到服务器端解析json数据，将json数据解析成javabean对象。不知道对初学者有没有帮助，又不懂的可以直接@我，