HttpClient、FastJson将json转换为JavaBean

HttpClient

一、HttpClient简介

HttpClient 是Apache Jakarta Common 下的子项目，可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。
HTTP 协议可能是现在 Internet 上使用得最多、最重要的协议了，越来越多的 Java 应用程序需要直接通过 HTTP 协议来访问网络资源。虽然在 JDK 的 java net包中已经提供了访问 HTTP 协议的基本功能，但是对于大部分应用程序来说，JDK 库本身提供的功能还不够丰富和灵活。HttpClient 是 Apache Jakarta Common 下的子项目，用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。HttpClient 已经应用在很多的项目中，比如 Apache Jakarta 上很著名的另外两个开源项目 Cactus 和 HTMLUnit 都使用了 HttpClient。

二、FastJson

1、FastJson简介

Fastjson 是一个 Java 库，可以将 Java 对象转换为 JSON 格式，当然它也可以将 JSON 字符串转换为 Java 对象。

Fastjson 可以操作任何 Java 对象，即使是一些预先存在的没有源码的对象。

Fastjson 源码地址：https://github.com/alibaba/fastjson

Fastjson 中文 Wiki：https://github.com/alibaba/fastjson/wiki/Quick-Start-CN

FastJson特性

提供服务器端、安卓客户端两种解析工具，性能表现较好。

提供了 toJSONString() 和 parseObject() 方法来将 Java 对象与 JSON 相互转换。调用toJSONString方 法即可将对象转换成 JSON 字符串，parseObject 方法则反过来将 JSON 字符串转换成对象。

允许转换预先存在的无法修改的对象（只有class、无源代码）。

Java泛型的广泛支持。

允许对象的自定义表示、允许自定义序列化类。

支持任意复杂对象（具有深厚的继承层次和广泛使用的泛型类型）。

例子

1、GetData.java：使用httpclient接收数据、再用fastJson将json数据解析为JavaBean。

package com.get_data.get;import java.io.IOException;import com.alibaba.fastjson.JSON;import org.apache.http.Header;import org.apache.http.HttpEntity;import org.apache.http.HttpResponse;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.HttpClient;import org.apache.http.client.methods.HttpGet;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.util.EntityUtils;public class GetData {    public static void main(String[] args) {        HttpClient client = new DefaultHttpClient();        //创建get请求实例        //HttpGet get = new HttpGet("http://www.baidu.com");        HttpGet get = new HttpGet("http://localhost:7333/a");        System.out.println("请求的uri为:"+get.getURI());        try {            // 客户端执行get请求 返回响应实体            HttpResponse response = client.execute(get);            //获取请求状态行            System.out.println("请求状态行为:"+response.getStatusLine());            //获取所有的请求头            Header[] headers=response.getAllHeaders();            for (Header header :headers){            //遍历获取所有请求头的名称和值            System.out.println(header.getName()+" :--: "+header.getValue());            }            System.out.println("-----------------------------------------------");            //获取响应的实体            HttpEntity entity =response.getEntity();            if (entity!=null){            String str=EntityUtils.toString(entity,"UTF-8");            System.out.println("entity:"+str);            System.out.println("获取到的json为："+str);            User newUser = JSON.parseObject(str, User.class);            System.out.println("User: "+newUser);            System.out.println("newUser.getAddress(): "+newUser.getAddress());            //System.out.println(EntityUtils.toString(entity,"UTF-8"));            System.out.println("=================================");            System.out.println("内容长度为:"+entity.getContentLength());        }        } catch (ClientProtocolException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }finally{            //释放连接            client.getConnectionManager().shutdown();        }    }}

2、http://localhost:7333/a返回的json数据

{    "name":"James",    "age":18,    "address":"chongqing"}

3、User.java实体类

public class User {    private String name;    private int age;    private String sex;    public String getSex() {        return sex;    }    public void setSex(String sex) {        this.sex = sex;    }    private String address;    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    public String getAddress() {        return address;    }    public void setAddress(String address) {        this.address = address;    }    @Override    public String toString() {        return "User{" +                "name='" + name + '\'' +                ", age=" + age +                ", address='" + address + '\'' +                '}';    }}

4、

输出结果：

请求的uri为:http://localhost:7333/a14:31:04.341 [main] DEBUG org.apache.http.impl.conn.BasicClientConnectionManager - Get connection for route {}->http://localhost:733314:31:04.387 [main] DEBUG org.apache.http.impl.conn.DefaultClientConnectionOperator - Connecting to localhost:733314:31:04.403 [main] DEBUG org.apache.http.client.protocol.RequestAddCookies - CookieSpec selected: default14:31:04.403 [main] DEBUG org.apache.http.client.protocol.RequestAuthCache - Auth cache not set in the context14:31:04.403 [main] DEBUG org.apache.http.client.protocol.RequestTargetAuthentication - Target auth state: UNCHALLENGED14:31:04.403 [main] DEBUG org.apache.http.client.protocol.RequestProxyAuthentication - Proxy auth state: UNCHALLENGED14:31:04.403 [main] DEBUG org.apache.http.impl.client.DefaultHttpClient - Attempt 1 to execute request14:31:04.403 [main] DEBUG org.apache.http.impl.conn.DefaultClientConnection - Sending request: GET /a HTTP/1.114:31:04.403 [main] DEBUG org.apache.http.wire -  >> "GET /a HTTP/1.1[\r][\n]"14:31:04.403 [main] DEBUG org.apache.http.wire -  >> "Host: localhost:7333[\r][\n]"14:31:04.403 [main] DEBUG org.apache.http.wire -  >> "Connection: Keep-Alive[\r][\n]"14:31:04.403 [main] DEBUG org.apache.http.wire -  >> "User-Agent: Apache-HttpClient/4.5.2 (Java/1.8.0_161)[\r][\n]"14:31:04.403 [main] DEBUG org.apache.http.wire -  >> "[\r][\n]"14:31:04.403 [main] DEBUG org.apache.http.headers - >> GET /a HTTP/1.114:31:04.403 [main] DEBUG org.apache.http.headers - >> Host: localhost:733314:31:04.403 [main] DEBUG org.apache.http.headers - >> Connection: Keep-Alive14:31:04.403 [main] DEBUG org.apache.http.headers - >> User-Agent: Apache-HttpClient/4.5.2 (Java/1.8.0_161)14:31:04.419 [main] DEBUG org.apache.http.wire -  << "HTTP/1.1 200 [\r][\n]"14:31:04.434 [main] DEBUG org.apache.http.wire -  << "Content-Type: application/json;charset=UTF-8[\r][\n]"14:31:04.434 [main] DEBUG org.apache.http.wire -  << "Transfer-Encoding: chunked[\r][\n]"14:31:04.434 [main] DEBUG org.apache.http.wire -  << "Date: Tue, 01 Jan 2019 06:31:04 GMT[\r][\n]"14:31:04.434 [main] DEBUG org.apache.http.wire -  << "[\r][\n]"14:31:04.434 [main] DEBUG org.apache.http.impl.conn.DefaultClientConnection - Receiving response: HTTP/1.1 200 14:31:04.434 [main] DEBUG org.apache.http.headers - << HTTP/1.1 200 14:31:04.434 [main] DEBUG org.apache.http.headers - << Content-Type: application/json;charset=UTF-814:31:04.434 [main] DEBUG org.apache.http.headers - << Transfer-Encoding: chunked14:31:04.434 [main] DEBUG org.apache.http.headers - << Date: Tue, 01 Jan 2019 06:31:04 GMT14:31:04.434 [main] DEBUG org.apache.http.impl.client.DefaultHttpClient - Connection can be kept alive indefinitely请求状态行为:HTTP/1.1 200 Content-Type :--: application/json;charset=UTF-8Transfer-Encoding :--: chunkedDate :--: Tue, 01 Jan 2019 06:31:04 GMT-----------------------------------------------14:31:04.450 [main] DEBUG org.apache.http.wire -  << "2f[\r][\n]"14:31:04.450 [main] DEBUG org.apache.http.wire -  << "{"name":"James","age":18,"address":"chongqing"}"14:31:04.450 [main] DEBUG org.apache.http.wire -  << "[\r][\n]"14:31:04.450 [main] DEBUG org.apache.http.wire -  << "0[\r][\n]"14:31:04.450 [main] DEBUG org.apache.http.wire -  << "[\r][\n]"14:31:04.450 [main] DEBUG org.apache.http.impl.conn.BasicClientConnectionManager - Releasing connection org.apache.http.impl.conn.ManagedClientConnectionImpl@4d3167f414:31:04.450 [main] DEBUG org.apache.http.impl.conn.BasicClientConnectionManager - Connection can be kept alive indefinitelyentity:{"name":"James","age":18,"address":"chongqing"}获取到的json为：{"name":"James","age":18,"address":"chongqing"}User: User{name='James', age=18, address='chongqing'}newUser.getAddress(): chongqing=================================内容长度为:-114:31:04.590 [main] DEBUG org.apache.http.impl.conn.DefaultClientConnection - Connection 0.0.0.0:64518<->127.0.0.1:7333 closedProcess finished with exit code 0