HttpClient跨域访问技术（导一个依赖，两个配置类，一个工具类，最后是怎么运用）
org.apache.httpcomponents
httpclient
httpClient.properties配置文件
#最大连接数
http.maxTotal = 1000
#并发数
http.defaultMaxPerRoute = 20
#创建连接的最长时间
http.connectTimeout=5000
#从连接池中获取到连接的最长时间
http.connectionRequestTimeout=500
#数据传输的最长时间
http.socketTimeout=5000
#提交请求前测试连接是否可用
http.staleConnectionCheckEnabled=true
HttpClientConfig配置类，写在配置包中
@Configuration
@PropertySource(value="classpath:/properties/httpClient.properties")
public class HttpClientConfig {
@Value("${http.maxTotal}")
private Integer maxTotal; //最大连接数
@Value("${http.defaultMaxPerRoute}")
private Integer defaultMaxPerRoute; //最大并发链接数
@Value("${http.connectTimeout}")
private Integer connectTimeout; //创建链接的最大时间
@Value("${http.connectionRequestTimeout}")
private Integer connectionRequestTimeout; //链接获取超时时间
@Value("${http.socketTimeout}")
private Integer socketTimeout; //数据传输最长时间
@Value("${http.staleConnectionCheckEnabled}")
private boolean staleConnectionCheckEnabled; //提交时检查链接是否可用
//定义httpClient链接池
@Bean(name="httpClientConnectionManager")
public PoolingHttpClientConnectionManager getPoolingHttpClientConnectionManager() {
PoolingHttpClientConnectionManager manager = new PoolingHttpClientConnectionManager();
manager.setMaxTotal(maxTotal); //设定最大链接数
manager.setDefaultMaxPerRoute(defaultMaxPerRoute); //设定并发链接数
return manager;
}
//定义HttpClient
/**
* 实例化连接池，设置连接池管理器。
* 这里需要以参数形式注入上面实例化的连接池管理器
@Qualifier 指定bean标签进行注入
*/
@Bean(name = "httpClientBuilder")
public HttpClientBuilder getHttpClientBuilder(@Qualifier("httpClientConnectionManager")PoolingHttpClientConnectionManager httpClientConnectionManager){
//HttpClientBuilder中的构造方法被protected修饰，所以这里不能直接使用new来实例化一个HttpClientBuilder,可以使用HttpClientBuilder提供的静态方法create()来获取HttpClientBuilder对象
HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();
httpClientBuilder.setConnectionManager(httpClientConnectionManager);
return httpClientBuilder;
}
/**
* 注入连接池，用于获取httpClient
* @param httpClientBuilder
* @return
*/
@Bean
public CloseableHttpClient getCloseableHttpClient(@Qualifier("httpClientBuilder") HttpClientBuilder httpClientBuilder){
return httpClientBuilder.build();
}
/**
* Builder是RequestConfig的一个内部类
* 通过RequestConfig的custom方法来获取到一个Builder对象
* 设置builder的连接信息
* @return
*/
@SuppressWarnings("deprecation")
@Bean(name = "builder")
public RequestConfig.Builder getBuilder(){
RequestConfig.Builder builder = RequestConfig.custom();
return builder.setConnectTimeout(connectTimeout)
.setConnectionRequestTimeout(connectionRequestTimeout)
.setSocketTimeout(socketTimeout)
.setStaleConnectionCheckEnabled(staleConnectionCheckEnabled);
}
/**
* 使用builder构建一个RequestConfig对象
* @param builder
* @return
*/
@Bean
public RequestConfig getRequestConfig(@Qualifier("builder") RequestConfig.Builder builder){
return builder.build();
}
}
（3）HttpClientClose配置类，写在配置包中
@Component //交给spring容器管理
public class HttpClientClose extends Thread{
@Autowired
private PoolingHttpClientConnectionManager manage;
private volatile boolean shutdown; //开关 volatitle表示多线程可变数据,一个线程修改,其他线程立即修改
public HttpClientClose() {
///System.out.println("执行构造方法,实例化对象");
//线程开启启动
this.start();
}
@Override
public void run() {
try {
//如果服务没有关闭,执行线程
while(!shutdown) {
synchronized (this) {
wait(5000); //等待5秒
//System.out.println("线程开始执行,关闭超时链接");
//关闭超时的链接
PoolStats stats = manage.getTotalStats();
int av = stats.getAvailable(); //获取可用的线程数量
int pend = stats.getPending(); //获取阻塞的线程数量
int lea = stats.getLeased(); //获取当前正在使用的链接数量
int max = stats.getMax();
//System.out.println("max/"+max+": av/"+av+": pend/"+pend+": lea/"+lea);
manage.closeExpiredConnections();
}
}
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException();
}
super.run();
}
//关闭清理无效连接的线程
@PreDestroy //容器关闭时执行该方法.
public void shutdown() {
shutdown = true;
synchronized (this) {
//System.out.println("关闭全部链接!!");
notifyAll(); //全部从等待中唤醒.执行关闭操作;
}
}
}
工具类，防止工具包中
/**工具类：通过此工具类实现服务器之间的 “跨域访问”，有doGet,doPost 注意：配置*/
@Service
public class HttpClientService {
@Autowired//通过连接池HttpClientBuilder，用于获取httpClient
private CloseableHttpClient httpClient;
@Autowired//设定请求的超时时间等
private RequestConfig requestConfig;
public String doGet(String url,Map params,String charset){
String result = null;
//1.判断字符集编码是否为空 如果为空则给定默认值utf-8
if(StringUtils.isEmpty(charset)) {
charset="UTF-8";
}
/**
* 2.http://manage.jt.com/items/10010
* http://manage.jt.com/items/10010?id=1&name=xxx
* 判断用户是否传递参数.
* Map>
*/
if(params!=null) {
url+="?";//第一步拼接?号
for (Map.Entry enty : params.entrySet()) {
String key = enty.getKey();
String value = enty.getValue();
url+=key+"="+value+"&";
}
//去除多余的&符
url=url.substring(0, url.length()-1);
}
//3.定义参数提交对象
HttpGet get = new HttpGet(url);
//4.为请求设定超时时间
get.setConfig(requestConfig);
//5.通过httpClient发送请求
try {
CloseableHttpResponse response =
httpClient.execute(get);
if(response.getStatusLine().getStatusCode() == 200){
//表示程序调用成功
result = EntityUtils.toString(response.getEntity(),charset);
}else{
System.out.println("调用异常:状态信息:"+response.getStatusLine().getStatusCode());
throw new RuntimeException();
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
public String doGet(String url){
return doGet(url, null, null);
}
public String doGet(String url,Map params){
return doGet(url, params, null);
}
public String doGet(String url,String charset){
return doGet(url, null, charset);
}
//实现httpClient POST提交
public String doPost(String url,Map params,String charset){
String result = null;
//1.定义请求类型
HttpPost post = new HttpPost(url);
post.setConfig(requestConfig); //定义超时时间
//2.判断字符集是否为null
if(StringUtils.isEmpty(charset)){
charset = "UTF-8";
}
//3.判断用户是否传递参数
if(params !=null){
//3.2准备List集合信息
List parameters =
new ArrayList<>();
//3.3将数据封装到List集合中
for (Map.Entry entry : params.entrySet()) {
parameters.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
}
//3.1模拟表单提交
try {
UrlEncodedFormEntity formEntity =
new UrlEncodedFormEntity(parameters,charset); //采用u8编码
//3.4将实体对象封装到请求对象中
post.setEntity(formEntity);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
//4.发送请求
try {
CloseableHttpResponse response =
httpClient.execute(post);
//4.1判断返回值状态
if(response.getStatusLine().getStatusCode() == 200) {
//4.2表示请求成功
result = EntityUtils.toString(response.getEntity(),charset);
}else{
System.out.println("获取状态码信息:"+response.getStatusLine().getStatusCode());
throw new RuntimeException();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return result;
}
public String doPost(String url){
return doPost(url, null, null);
}
public String doPost(String url,Map params){
return doPost(url, params, null);
}
public String doPost(String url,String charset){
return doPost(url, null, charset);
}
}
测试实践类
public class ItemServiceImpl implements ItemService{
@Autowired
private HttpClientService httpClient;
@CacheFind
@Override//前台服务器jt-web模拟HTTP协议，发送地址到后台服务器jt-manage取数据，然后返回给前台jt-web
public Item findItemById(Long itemId) {
String url="http://manage.jt.com/web/item/findItemById";
Map params = new HashMap<>();
params.put("itemId", itemId+"");
String json = httpClient.doGet(url, params);
return ObjectMapperUtill.toObject(json, Item.class);
}
@CacheFind
@Override//前台服务器jt-web模拟HTTP协议，发送地址到后台服务器jt-manage取数据，然后返回给前台jt-web
public ItemDesc findItemDescById(Long itemId) {
String url="http://manage.jt.com/web/item/findItemDescById";
Map params = new HashMap<>();
params.put("itemId", itemId+"");
String json = httpClient.doGet(url, params);
return ObjectMapperUtill.toObject(json, ItemDesc.class);
}
}