多字段查询需要使用MultiFieldQueryParser来做解析：

String params[] = new String[]{par,par};

String fields[] = new String[]{"title","context"};

BooleanClause.Occur rules[] = new BooleanClause.Occur[]{BooleanClause.Occur.SHOULD,BooleanClause.Occur.SHOULD};

Query query = MultiFieldQueryParser.parse(params,fields,rules,analyzer);

其中par是查询关键字，params是根据需要查询的字段数定义的查询参数列表。以上可以翻译为：title like par or context like par。

fields是需要同时查询的字段列表。

analyzer是分词器，不必说。

rules是定义多个参数的匹配规则列表，总共有以下几种情况：

/** Use this operator for clauses that <i>must</i> appear in the matching documents. */
MUST     { @Override public String toString() { return "+"; } },

/** Like {@link #MUST} except that these clauses do not participate in scoring. */
FILTER   { @Override public String toString() { return "#"; } },

/** Use this operator for clauses that <i>should</i> appear in the 
 * matching documents. For a BooleanQuery with no <code>MUST</code> 
 * clauses one or more <code>SHOULD</code> clauses must match a document 
 * for the BooleanQuery to match.
 * @see BooleanQuery.Builder#setMinimumNumberShouldMatch
 */
SHOULD   { @Override public String toString() { return "";  } },

/** Use this operator for clauses that <i>must not</i> appear in the matching documents.
 * Note that it is not possible to search for queries that only consist
 * of a <code>MUST_NOT</code> clause. These clauses do not contribute to the
 * score of documents. */
MUST_NOT { @Override public String toString() { return "-"; } };