HttpClient、FastJson將json轉換為JavaBean
阿新 • • 發佈：2019-01-08
HttpClient
一、HttpClient簡介
HttpClient 是Apache Jakarta Common 下的子專案，可以用來提供高效的、最新的、功能豐富的支援 HTTP 協議的客戶端程式設計工具包，並且它支援 HTTP 協議最新的版本和建議。
HTTP 協議可能是現在 Internet 上使用得最多、最重要的協議了，越來越多的 Java 應用程式需要直接通過 HTTP 協議來訪問網路資源。雖然在 JDK 的 java net包中已經提供了訪問 HTTP 協議的基本功能，但是對於大部分應用程式來說，JDK 庫本身提供的功能還不夠豐富和靈活。HttpClient 是 Apache Jakarta Common 下的子專案，用來提供高效的、最新的、功能豐富的支援 HTTP 協議的客戶端程式設計工具包，並且它支援 HTTP 協議最新的版本和建議。HttpClient 已經應用在很多的專案中，比如 Apache Jakarta 上很著名的另外兩個開源專案 Cactus 和 HTMLUnit 都使用了 HttpClient。
二、FastJson
1、FastJson簡介
Fastjson 是一個 Java 庫，可以將 Java 物件轉換為 JSON 格式，當然它也可以將 JSON 字串轉換為 Java 物件。
Fastjson 可以操作任何 Java 物件，即使是一些預先存在的沒有原始碼的物件。
Fastjson 原始碼地址：https://github.com/alibaba/fastjson
Fastjson 中文 Wiki：https://github.com/alibaba/fastjson/wiki/Quick-Start-CN
FastJson特性
提供伺服器端、安卓客戶端兩種解析工具，效能表現較好。
提供了 toJSONString() 和 parseObject() 方法來將 Java 物件與 JSON 相互轉換。呼叫toJSONString方 法即可將物件轉換成 JSON 字串，parseObject 方法則反過來將 JSON 字串轉換成物件。
允許轉換預先存在的無法修改的物件（只有class、無原始碼）。
Java泛型的廣泛支援。
允許物件的自定義表示、允許自定義序列化類。
支援任意複雜物件（具有深厚的繼承層次和廣泛使用的泛型型別）。
例子
1、GetData.java：使用httpclient接收資料、再用fastJson將json資料解析為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(); //建立get請求例項 //HttpGet get = new HttpGet("http://www.baidu.com"); HttpGet get = new HttpGet("http://localhost:7333/a"); System.out.println("請求的uri為:"+get.getURI()); try { // 客戶端執行get請求 返回響應實體 HttpResponse response = client.execute(get); //獲取請求狀態行 System.out.println("請求狀態行為:"+response.getStatusLine()); //獲取所有的請求頭 Header[] headers=response.getAllHeaders(); for (Header header :headers){ //遍歷獲取所有請求頭的名稱和值 System.out.println(header.getName()+" :--: "+header.getValue()); } System.out.println("-----------------------------------------------"); //獲取響應的實體 HttpEntity entity =response.getEntity(); if (entity!=null){ String str=EntityUtils.toString(entity,"UTF-8"); System.out.println("entity:"+str); System.out.println("獲取到的json為："+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("內容長度為:"+entity.getContentLength()); } } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); }finally{ //釋放連線 client.getConnectionManager().shutdown(); } } }
2、http://localhost:7333/a返回的json資料
{
"name":"James",
"age":18,
"address":"chongqing"
}3、User.java實體類
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、
輸出結果：
請求的uri為:http://localhost:7333/a
14:31:04.341 [main] DEBUG org.apache.http.impl.conn.BasicClientConnectionManager - Get connection for route {}->http://localhost:7333
14:31:04.387 [main] DEBUG org.apache.http.impl.conn.DefaultClientConnectionOperator - Connecting to localhost:7333
14:31:04.403 [main] DEBUG org.apache.http.client.protocol.RequestAddCookies - CookieSpec selected: default
14:31:04.403 [main] DEBUG org.apache.http.client.protocol.RequestAuthCache - Auth cache not set in the context
14:31:04.403 [main] DEBUG org.apache.http.client.protocol.RequestTargetAuthentication - Target auth state: UNCHALLENGED
14:31:04.403 [main] DEBUG org.apache.http.client.protocol.RequestProxyAuthentication - Proxy auth state: UNCHALLENGED
14:31:04.403 [main] DEBUG org.apache.http.impl.client.DefaultHttpClient - Attempt 1 to execute request
14:31:04.403 [main] DEBUG org.apache.http.impl.conn.DefaultClientConnection - Sending request: GET /a HTTP/1.1
14:31:04.403 [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/1.1
14:31:04.403 [main] DEBUG org.apache.http.headers - >> Host: localhost:7333
14:31:04.403 [main] DEBUG org.apache.http.headers - >> Connection: Keep-Alive
14:31:04.403 [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-8
14:31:04.434 [main] DEBUG org.apache.http.headers - << Transfer-Encoding: chunked
14:31:04.434 [main] DEBUG org.apache.http.headers - << Date: Tue, 01 Jan 2019 06:31:04 GMT
14:31:04.434 [main] DEBUG org.apache.http.impl.client.DefaultHttpClient - Connection can be kept alive indefinitely
請求狀態行為:HTTP/1.1 200
Content-Type :--: application/json;charset=UTF-8
Transfer-Encoding :--: chunked
Date :--: 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 [email protected]
14:31:04.450 [main] DEBUG org.apache.http.impl.conn.BasicClientConnectionManager - Connection can be kept alive indefinitely
entity:{"name":"James","age":18,"address":"chongqing"}
獲取到的json為：{"name":"James","age":18,"address":"chongqing"}
User: User{name='James', age=18, address='chongqing'}
newUser.getAddress(): chongqing
=================================
內容長度為:-1
14:31:04.590 [main] DEBUG org.apache.http.impl.conn.DefaultClientConnection - Connection 0.0.0.0:64518<->127.0.0.1:7333 closed
Process finished with exit code 0