當(dāng)你寫一段代碼很糾結(jié)時(shí)，不防停下來Google一下，一定有人已經(jīng)解決了你的煩惱！

一、背景

今天PM提出想給一個(gè)URL埋點(diǎn)，統(tǒng)計(jì)一下訪問來源，需要我在路徑上加一個(gè)參數(shù)fromPage=shop_detail;本來是一個(gè)很簡單的問題，因?yàn)樵溄痈緵]參數(shù)，只只需要在url后面加上?fromPage=shop_detail；可想了一下有安全隱患，萬一url變了，帶了參數(shù)怎么辦？于是想那我就自己判斷是否有參數(shù)，再決定加?或/;當(dāng)我下手寫的時(shí)候又糾結(jié)了，為了這么一點(diǎn)東西要寫好幾行代碼呢，不行，還是得先google 一下，就有了如下結(jié)論。

二、 添加parameter的方式

2.1 java.net.URI

通過string 生成URI，再通過URI獲取query,再通過query判斷是添加&或?; 似乎也挺麻煩……

package urItest;
 
import java.net.URI;
import java.net.URISyntaxException;
 
/**
 * Created by fuxiangxu on 2017/1/10.
 */
public class URITest {
    public static URI appendUri(String uri, String appendQuery) throws URISyntaxException {
        URI oldUri = new URI(uri);
 
        String newQuery = oldUri.getQuery();
        if (newQuery == null) {
            newQuery = appendQuery;
        } else {
            newQuery += "&" + appendQuery;
        }
 
        URI newUri = new URI(oldUri.getScheme(), oldUri.getAuthority(),
                oldUri.getPath(), newQuery, oldUri.getFragment());
 
        return newUri;
    }
 
    public static void main(String[] args) throws Exception {
        System.out.println(appendUri("http://example.com", "name=John"));
        System.out.println(appendUri("http://example.com#fragment", "name=John"));
        System.out.println(appendUri("http://example.com?email=john.doe@email.com", "name=John"));
        System.out.println(appendUri("http://example.com?email=john.doe@email.com#fragment", "name=John"));
    }
}

2.2 javax.ws.rs.core.UriBuilder

package urItest;
 
import javax.ws.rs.core.UriBuilder;
 
import java.net.URISyntaxException;
 
/**
 * Created by fuxiangxu on 2017/1/10.
 */
public class URIBuilderTest {
 
    public static void main(String[] args) throws URISyntaxException {
        System.out.println(UriBuilder.fromUri("http://example.com").queryParam("name", "john").build().toString());
        System.out.println(UriBuilder.fromUri("http://example.com?email=john.doe@email.com").queryParam("name", "john").build().toString());
    }
}

2.3 org.apache.http.client.utils.URIBuilder

package urItest;
 
import org.apache.http.client.utils.URIBuilder;
 
import java.net.URISyntaxException;
 
/**
 * Created by fuxiangxu on 2017/1/10.
 */
public class URIBuilderTest {
 
    public static void main(String[] args) throws URISyntaxException {
        System.out.println(new URIBuilder("http://example.com").addParameter("name", "john").build().toString());
        System.out.println(new URIBuilder("http://example.com?email=john.doe@email.com").addParameter("name", "john").build().toString());
    }
}

2.4 org.springframework.web.util.UriComponentsBuilder (建議)

package urItest;
 
import org.springframework.web.util.UriComponentsBuilder;
 
import java.net.URISyntaxException;
 
/**
 * Created by fuxiangxu on 2017/1/10.
 */
public class URIBuilderTest {
 
    public static void main(String[] args) throws URISyntaxException {
        System.out.println(UriComponentsBuilder.fromUriString("http://example.com").queryParam("name", "john").build().toString());
        System.out.println(UriComponentsBuilder.fromUriString("http://example.com?email=john.doe@email.com").queryParam("name", "john").build().toString());
    }
}