最后Search Query Sort类（列表6）实现了开发者对结果排序的控制。 public class SearchQuerySort {
private List<SearchRank> _ranks;
public SearchQuerySort(){
_ranks = new LinkedList<SearchRank>();
}
public void addRank(SearchRank rank){
_ranks.add(rank);
}
@Override
public String toString(){
if(_ranks.size() == 0)
return null;
StringBuffer sb = new StringBuffer();
sb.append("&rank=");
boolean first = true;
for(SearchRank r : _ranks){
if(!first)
sb.append("%2C");
else
first = false;
sb.append(r);
}
return sb.toString();
}
public static class SearchRank{
private String _name;
private boolean _ascending;
public SearchRank(){
_ascending = true;
}
public SearchRank(String name){
_ascending = true;
_name = name;
}
public SearchRank(String name, boolean ascending){
_ascending = ascending;
_name = name;
}
@Override
public String toString(){
if(_ascending)
return _name;
return "-" + _name;
}
}
}
Listing 6 Sort control class
CloudSearch查询除了将所有的参数汇总到一起，还增加了页码信息和一组返回字段。 这个查询类还提供了一个方法——HTTP查询转换（列表7），将搜索查询的所有部分汇总，并生成能被搜索处理的HTTP字符串。 public String toHttpQuery() throws Exception{
StringBuffer sb = new StringBuffer();
sb.append("?results-type=xml");
if(_size > 0){
sb.append("&size=");
sb.append(_size);
}
if(_start > 0){
sb.append("&start=");
sb.append(_start);
}
if((_fields != null) && (_fields.size() > 0)){
sb.append("&return-fields=");
boolean first = true;
for(String f : _fields){
if(!first)
sb.append("%2C");
else
first = false;
sb.append(f);
}
}
if(_filter != null){
if(_filter instanceof SearchQueryValueFilter)
sb.append("&q=");
else
sb.append("&bq=");
sb.append(URLEncoder.encode(_filter.toString(), "UTF8"));
}
if((_facets != null) && (_facets.size() > 0)){
for(SearchQueryFacet f : _facets){
sb.append(f);
}
}
if((_sorts != null) && (_sorts.size() > 0)){
for(SearchQuerySort s : _sorts){
sb.append(s);
}
}
return sb.toString();
}
Listing 7 Convert to HTTP query method
我们使用Apache HttpComponents来实现与亚马逊云搜索的通信。 测试我们的API我们使用亚马逊提供的IMDB样例来进行验证。首次单元测试（列表8）用于验证我们实现的搜索API。 public class SearchAPITester extends TestCase {
private static final String SearchURL = "search-imdb-movies-ab4fpqw4eocczpgsnrtlu4rn7i.us-east-
1.cloudsearch.amazonaws.com";
private CloudSearchClient client;
protected void setUp() throws Exception {
client = new CloudSearchClient(SearchURL);
}
protected void tearDown() {
client.close();
}
public void testSearch() throws Exception{
SearchQueryValueFilter f1 = new SearchQueryValueFilter("title", "star", false, false);
SearchQueryValueFilter f11 = new SearchQueryValueFilter("title", "war", false, true);
SearchQueryValueFilter f2 = new SearchQueryValueFilter("year", "..2000", true, false);
SearchQueryFilterOperation f12 = new SearchQueryFilterOperation();
f12.setOperation(FilterOperation.or);
f12.addFilters(f1);
f12.addFilters(f11);
SearchQueryFilterOperation f3 = new SearchQueryFilterOperation();
f3.addFilters(f12);
f3.addFilters(f2);
CloudSearchQuery query = new CloudSearchQuery(f3);
query.addField("actor");
query.addField("director");
query.addField("title");
query.addField("year");
SearchQueryFacet sf = new SearchQueryFacet("genre", 5, FacetSort.alpha);
sf.addConstraint("Drama");
sf.addConstraint("Sci-Fi");
query.addFacet(sf);
SearchQuerySort sort = new SearchQuerySort();
SearchRank r1 = new SearchRank("title");
SearchRank r2 = new SearchRank("year", false);
sort.addRank(r1);
sort.addRank(r2);
query.addSort(sort);
try {
System.out.println("Test 1 ");
SearchResults result = client.search(query);
System.out.println(result);
} catch (Exception e) {
e.printStackTrace();
}
}
}
Listing 8 Search API tester
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