android - 安卓读取json文件读不了...

Question

package com.example.Demo_9;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;

import java.io.IOException;

public class MyActivity extends Activity {
    /**
     * Called when the activity is first created.
     */
    private Button button;
    private String result="";
    private Handler handler;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        button = (Button) findViewById(R.id.button);
        final TextView textView = (TextView) findViewById(R.id.text);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        send();
                        Message m = handler.obtainMessage();
                        handler.sendMessage(m);
                    }
                }).start();
            }
        });

        handler = new Handler() {
            @Override
            public void handleMessage(Message msg) {

                if (result != null) {
                    textView.setText(result);
                }
                super.handleMessage(msg);
            }
        };
    }


    public void send() {
        String target = "http://192.168.1.161:8080/blog/demo.json";
        HttpClient client = new DefaultHttpClient();
        HttpPost requet = new HttpPost(target);
        HttpResponse response;


        try {
            response = client.execute(requet);
            if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                result = EntityUtils.toString(response.getEntity());

            } else {
                result = "connection failed!";  //
            }

        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

刚开始写这个，怎么老是得到 result = "connection failed!"; 呢？ 手机能够连接到tomcat服务器的demo.json文件的，这没问题的。我哪里逻辑错了吗？我想把json文件内容显示到textview上的....

Answer 1

每次看到有人用HttpClient我就是想先说：Google已经抛弃HttpClient了，6.0里已经把HttpClient库删除了，那么去解决你的问题还有意义吗？等把你的问题解决好了，你又怎么去解决版本兼容的问题呢？
先换了HTTP请求库再说吧。

Answer 2

伪代码大致如下：

final HttpPost httpPost = new HttpPost(url);
final List<NameValuePair> requestParams = new ArrayList<NameValuePair>();
HashMap<String, Object> paramsMap = new HashMap<String, Object>();
paramsMap.put("param", param);
requestParams.add(new BasicNameValuePair("body", params.to));
new Thread((new Runnable() {
    @Override
    public void run() {
        try {
            httpPost.setEntity(new UrlEncodedFormEntity(requestParams, ConstantsValue.ENCODING));
            HttpResponse httpResponse = new DefaultHttpClient().execute(httpPost);
            if (httpResponse.getStatusLine().getStatusCode() == 200) {
                result = EntityUtils.toString(httpResponse.getEntity());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        mHandler.sendMessage(Message.obtain(mHandler, tag));
    };
})).start();

最好自定义一个线程池，ThreadPoolExecutor 用起来很方便。

不过网络请求还是用 OkHttp 或者 Retrofit 吧，很方便的。

Answer 3

connection failed!是你自己定义的，根本没法看到返回什么信息。你还是调试一下看看Response中的返回码和信息吧

Answer 4

@有明 说的很对，还故意查了一下：