SpringBoot開發筆記-(5)-導入外部資源: @ImportResource

時間 2020-08-06

標籤 springboot 開發筆記導入外部資源 importresource 欄目 Spring 简体版

原文原文鏈接

上一節:SpringBoot開發筆記-(4) 屬性文件讀取2: @PropertySourcehtml

5.1 前情提要-場景

以前的2節都是講怎麼讀取配置文件; 可是若是有下列的狀況, 就須要用到@ImportResource來幫忙了:java

有一個遺留的xml文件, 好比名叫 spring-beans.xml 裏面有不少的配置bean, 都須要註冊到spring容器中, 讓容器來管理這些bean以備不時之需;
傳統springmvc的項目, 原來的xml配置文件不想刪除, 可是又想用springboot來改造它; 就可使用 @ImportResource來 導入外部資源

簡言之: 就是還想用xml, 還想用 springboot; xml就由此註解來註冊進去!web

5.2. 示例

啓動類上加註解: @ImportResource("classpath:/spring/spring-*.xml")

package com.niewj.springboot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ImportResource;

@SpringBootApplication
@ImportResource("classpath:/spring/spring-*.xml")
public class HelloApplication {

    public static void main(String[] args) {
        SpringApplication.run(HelloApplication.class, args);
    }

}

resource: spring/spring-html.xml文件:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.springframework.org/schema/beans
      http://www.springframework.org/schema/beans/spring-beans.xsd">

   <!-- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= -->
   <!-- RestTemplate -->
   <bean id="httpClient" class="com.niewj.springboot.utils.MyHttpClientUtils" factory-method="buildHttpClient"/>

   <bean id="clientHttpRequestFactory" class="org.springframework.http.client.HttpComponentsClientHttpRequestFactory">
       <property name="connectTimeout" value="20000"/><!-- 鏈接超時 -->
       <property name="readTimeout" value="30000"/><!-- 數據讀取超時時間 -->
       <property name="connectionRequestTimeout" value="20000"/> <!-- 鏈接不夠用的等待時間 -->
       <constructor-arg ref="httpClient"/>
   </bean>

   <bean id="restTemplate" class=" org.springframework.web.client.RestTemplate">
       <constructor-arg ref="clientHttpRequestFactory"/>
   </bean>
</beans>

這個xml中但願獲得一個 RestTemplate的bean, 須要依賴一個httpClient, httpClient代碼咱們本身寫的, 以下:spring

package com.niewj.springboot.utils;

import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.apache.http.conn.socket.PlainConnectionSocketFactory;
import org.apache.http.conn.ssl.NoopHostnameVerifier;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.TrustStrategy;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.ssl.SSLContextBuilder;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.SSLContext;
import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

/**
 * Created by niewj on 2019/04/10.
 */
public class MyHttpClientUtils {

    public static CloseableHttpClient buildHttpClient() throws KeyStoreException, NoSuchAlgorithmException, KeyManagementException {
        HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();

        // setup a Trust Strategy that allows all certificates.
        //
        SSLContext sslContext = new SSLContextBuilder().loadTrustMaterial(null, new TrustStrategy() {
            @Override
            public boolean isTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {
                return true;
            }
        }).build();
        httpClientBuilder.setSSLContext(sslContext);

        HostnameVerifier hostnameVerifier = NoopHostnameVerifier.INSTANCE;

        // 這是特殊的部分:
        //      -- need to create an SSL Socket Factory, to use our weakened "trust strategy";
        //      -- and create a Registry, to register it.
        //
        SSLConnectionSocketFactory sslSocketFactory = new SSLConnectionSocketFactory(sslContext, hostnameVerifier);

        // 註冊http和https請求
        Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory>create()
                .register("http", PlainConnectionSocketFactory.getSocketFactory())
                .register("https", sslSocketFactory).build();
        // 開始設置鏈接池-- allows multi-threaded use
        PoolingHttpClientConnectionManager connMgr = new PoolingHttpClientConnectionManager(socketFactoryRegistry);
        // 最大鏈接數200
        connMgr.setMaxTotal(200);
        // 同路由併發數100
        connMgr.setDefaultMaxPerRoute(100);
        httpClientBuilder.setConnectionManager(connMgr);
        // 重試次數
        httpClientBuilder.setRetryHandler(new DefaultHttpRequestRetryHandler(3, true));
        CloseableHttpClient client = httpClientBuilder.build();

        return client;
    }

}

在此例中, 這個類自己並不重要, 重要的是 xml中配置的bean id, 要最終在spring容器中可以檢索到, 拿出對象;shell

測試用例:apache

package com.niewj.springboot;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.web.client.RestTemplate;

import java.util.Arrays;
import java.util.Optional;

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootTest {

    @Autowired
    private ApplicationContext ctx;

    @Test
    public void testImportResurce() {
        // 從spring容器中拿到容器管理的全部bean定義, 而後過濾 bean的id, 看有沒有叫 restTemplate的:
        Optional<String> restTemplate = Arrays.stream(ctx.getBeanDefinitionNames()).filter(s -> s.equalsIgnoreCase("restTemplate")).findAny();
        String template = restTemplate.orElse(null);
        // 若是有, 打印出對象
        if(null != template){
            System.out.println(ctx.getBean(RestTemplate.class));
        }
    }
}

輸出:segmentfault

org.springframework.web.client.RestTemplate@2dd8239

若是把 @ImportResource這一行註釋掉: 就什麼都不會輸出了!!!springboot

package com.niewj.springboot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ImportResource;

@SpringBootApplication
//@ImportResource("classpath:/spring/spring-*.xml")
public class HelloApplication {

    public static void main(String[] args) {
        SpringApplication.run(HelloApplication.class, args);
    }

}