MYSQL java.lang.OutOfMemoryError: Java heap space

今天使用jdbc的PreparedStatement查詢語句如下：

Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/translate?characterEncoding=utf8";
        String sql = "select id, title, search_title, content from article";
        Connection conn = DriverManager.getConnection(url, 
"root", "123456");
        PreparedStatement ps = conn.prepareStatement(sql);
        ResultSet rs = ps.executeQuery();
        rs.close();
        ps.close();
        conn.close();

Class.forName("com.mysql.jdbc.Driver"); String url = "jdbc:mysql://localhost:3306/translate?characterEncoding=utf8"; String sql = "select id, title, search_title, content from article"; Connection conn = DriverManager.getConnection(url, "root", "123456"); PreparedStatement ps = conn.prepareStatement(sql); ResultSet rs = ps.executeQuery(); rs.close(); ps.close(); conn.close();

總是報這個錯誤：

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at com.mysql.jdbc.Buffer.getBytes(Buffer.java:198)
at com.mysql.jdbc.Buffer.readLenByteArray(Buffer.java:318)
at com.mysql.jdbc.MysqlIO.extractNativeEncodedColumn(MysqlIO.java:3567)
at com.mysql.jdbc.MysqlIO.unpackBinaryResultSetRow(MysqlIO.java:3483)
at com.mysql.jdbc.MysqlIO.nextRow(MysqlIO.java:1391)
at com.mysql.jdbc.MysqlIO.readSingleRowSet(MysqlIO.java:2369)
at com.mysql.jdbc.MysqlIO.getResultSet(MysqlIO.java:451)
at com.mysql.jdbc.MysqlIO.readResultsForQueryOrUpdate(MysqlIO.java:2076)
at com.mysql.jdbc.MysqlIO.readAllResults(MysqlIO.java:1451)
at com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement.java:1314)
at com.mysql.jdbc.ServerPreparedStatement.executeInternal(ServerPreparedStatement.java:740)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1467)

但是從網上找到的doc說，默認情況下不會出這個問題的，因爲java回自動的優化不會導致內存溢出的。百思不得其解。

後來無意找到一個介紹，這麼來做

就是給url連接字符串添加2個屬性即可：useCursorFetch=true&defaultFetchSize=100