JDBC获取数据库返回的多个结果集

问题描述：有时使用JDBC进行数据库查询时会返回多个结果集，但是PreparedStatement方式只能接收第一个结果集。
例如在SQL Server中执行sp_help 'test.student'，该语句会返回至少7个结果集。

1、使用PreparedStatement进行JDBC操作

public class MSSqlTest {
    public static void main(String[] args) {
        System.out.println(getOneResultSet());
    }

    public static List<Map> getOneResultSet() {
        List<Map> result = new ArrayList<>();

        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;

        try {
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            conn = DriverManager.getConnection("jdbc:sqlserver://192.168.14.172:11433;" +
                    "databaseName=test;instanceName=test", "sa", "FFCSffcs8!");
            // 该语句会返回多个结果集
            pstmt = conn.prepareCall("sp_help 'test.student'");
            rs = pstmt.executeQuery();
            while (rs.next()) {
                ResultSetMetaData rsmd = rs.getMetaData();
                int columnCount = rsmd.getColumnCount();
                Map map = new HashMap();
                for (int i = 0; i < columnCount; i++) {
                    map.put(rsmd.getColumnName(i + 1).toLowerCase(), rs.getObject(i + 1));
                }
                result.add(map);
            }
        }catch (Exception e) {
            System.out.println(e.getMessage());
        }finally{
            if(null !=rs ){
                try {
                    rs.close();
                } catch (SQLException ex) {
                }
            }
            if(null != pstmt){
                try {
                    pstmt.close();
                } catch (SQLException ex) {
                }
            }
            if(null != conn){
                try {
                    conn.close();
                } catch (SQLException ex) {
                }
            }
        }
        return result;
    }
}

调用该方法只会返回第一个结果集的内容：

[{owner=dbo, name=student, type=user table, created_datetime=2019-01-08 06:53:33.163}]

2、使用CallableStatement进行JDBC操作

public class MSSqlTest {
    public static void main(String[] args) {
       int resultCount = 0;
       for (List<Map> maps : getMoreResultSet()) {
           System.out.println("结果集" + resultCount++ + " : ");
           System.out.println(JSON.toJSONString(maps));
       }
    }

    public static List<List<Map>> getMoreResultSet() {
        List<List<Map>> resultList = new ArrayList<>();
        
        Connection conn = null;
        CallableStatement cstmt = null;
        ResultSet rs = null;

        try {
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            conn = DriverManager.getConnection("jdbc:sqlserver://192.168.14.172:11433;" +
                    "databaseName=test;instanceName=test", "sa", "FFCSffcs8!");
            // 该语句会返回多个结果集
            cstmt = conn.prepareCall("sp_help 'test.student'");
            rs = cstmt.executeQuery();
            boolean oprFlg = cstmt.execute();
            // 外循环获取结果集的个数
            while (oprFlg) {
                List<Map> result = new ArrayList<>();
                rs = cstmt.getResultSet();
                // 内循环获取每个结果集的记录
                while (rs.next()) {
                    ResultSetMetaData rsmd = rs.getMetaData();
                    int columnCount = rsmd.getColumnCount();
                    Map map = new HashMap();
                    for (int i = 0; i < columnCount; i++) {
                        map.put(rsmd.getColumnName(i + 1).toLowerCase(), rs.getObject(i + 1));
                    }
                    result.add(map);
                }
                resultList.add(result);
                oprFlg = cstmt.getMoreResults();
            }
        }catch (Exception e) {
            System.out.println(e.getMessage());
        }finally{
            if(null !=rs ){
                try {
                    rs.close();
                } catch (SQLException ex) {
                }
            }
            if(null != cstmt){
                try {
                    cstmt.close();
                } catch (SQLException ex) {
                }
            }
            if(null != conn){
                try {
                    conn.close();
                } catch (SQLException ex) {
                }
            }
        }
        return resultList;
    }
}

此时便可以获取所有结果集：

结果集0 : 
[{"owner":"dbo","name":"student","type":"user table","created_datetime":1546901613163}]
结果集1 : 
[{"trimtrailingblanks":"(n/a)","fixedlennullinsource":"(n/a)","computed":"no","prec":"10   ","nullable":"no","column_name":"c_id","length":4,"scale":"0    ","type":"int"},{"trimtrailingblanks":"no","fixedlennullinsource":"yes","computed":"no","prec":"     ","nullable":"yes","column_name":"c_name","length":200,"scale":"     ","collation":"SQL_Latin1_General_CP1_CI_AS","type":"varchar"},{"trimtrailingblanks":"(n/a)","fixedlennullinsource":"(n/a)","computed":"no","prec":"10   ","nullable":"no","column_name":"c_age","length":4,"scale":"0    ","type":"int"},{"trimtrailingblanks":"(n/a)","fixedlennullinsource":"(n/a)","computed":"no","prec":"10   ","nullable":"yes","column_name":"s_id","length":4,"scale":"0    ","type":"int"}]
结果集2 : 
[{"identity":"No identity column defined."}]
结果集3 : 
[{"rowguidcol":"No rowguidcol column defined."}]
结果集4 : 
[{"data_located_on_filegroup":"PRIMARY"}]
结果集5 : 
[{"index_description":"clustered, unique, primary key located on PRIMARY","index_keys":"c_id","index_name":"PK__student__213EE774F2EB6C88"}]
结果集6 : 
[{"update_action":"(n/a)","constraint_type":"DEFAULT on column c_age","status_for_replication":"(n/a)","constraint_name":"DF__student__c_age__440B1D61","delete_action":"(n/a)","status_enabled":"(n/a)","constraint_keys":"((18))"},{"update_action":"(n/a)","constraint_type":"DEFAULT on column c_name","status_for_replication":"(n/a)","constraint_name":"DF__student__c_name__4316F928","delete_action":"(n/a)","status_enabled":"(n/a)","constraint_keys":"('jack')"},{"update_action":"(n/a)","constraint_type":"PRIMARY KEY (clustered)","status_for_replication":"(n/a)","constraint_name":"PK__student__213EE774F2EB6C88","delete_action":"(n/a)","status_enabled":"(n/a)","constraint_keys":"c_id"}]
结果集7 : 
[{"table is referenced by foreign key":"TEST.test.test: FK__test__s_id__6D0D32F4"}]