String query = "select * from all_element t where t.task_id in (" ; StringBuilder queryBuilder = new StringBuilder(query); for ( int i = 0; i < taskIds.size(); i++) { queryBuilder.append( " ?" ); if (i != taskIds.size() - 1) queryBuilder.append( "," ); } queryBuil...
String query ="select * from all_element t where t.task_id in ("; StringBuilder queryBuilder =newStringBuilder(query); for(inti = 0; i < taskIds.size(); i++) { queryBuilder.append(" ?"); if(i != taskIds.size() - 1) queryBuilder.append(","); } queryBuilder.append(")");...
1//使用Statement的弊端:需要拼写sql语句,并且存在SQL注入的问题2@Test3publicvoidtestLogin() {4Scanner scan =newScanner(System.in);56System.out.print("用户名:");7String userName =scan.nextLine();8System.out.print("密 码:");9String password =scan.nextLine();1011//SELECT user,password FROM u...
// Method :public PreparedStatement prepareStatement(String query)throws SQLException{}// Usage :Connection con = DriverManager.getConnection ("jdbc:mysql://localhost:3306/customerdb", "root", "root");PreparedStatement ps = con.prepareStatement("select id, firstname, lastname, email, birthdate from...
SQL Query 2:使用参数化查询的PreparedStatement 代码语言:javascript 代码运行次数:0 运行 AI代码解释 PreparedStatement prestmt=conn.prepareStatement("select banks from loan where loan_type=?");prestmt.setString(1,loanType); 第二个查询就是正确使用PreparedStatement的查询,它比SQL1能获得更好的性能。
AS performance_schema, @@query_cache_size AS query_cache_size, @@query_cache_type AS query_...
inttimeoutInSeconds=60;// 设置超时时间为60秒statement.setQueryTimeout(timeoutInSeconds); 1. 2. 3.4 执行查询或更新操作 现在,我们可以执行查询或更新操作了。执行查询操作可以通过调用executeQuery()方法,而执行更新操作可以通过调用executeUpdate()方法。下面是一个执行查询操作的示例代码: ...
executeQuery 执行SELECT,返回结果集 executeUpdate 执行INSERT UPDATE DELETE 以及SQL DDL(数据定义语言)语句,返回受影响的行 execute可以执行所有SQL,所以他可能返回结果集,也可能返回受影响的行 所以execute的返回值用于区分是返回的结果集还是受影响的行,换句话说,true表示SELECT false表示INSERT UPDATE DELETE ...
SQL Query 1:字符串追加形式的PreparedStatement String loanType = getLoanType(); PreparedStatement prestmt = conn.prepareStatement("select banks from loan where loan_type=" + loanType); SQL Query 2:使用参数化查询的PreparedStatement PreparedStatement prestmt = conn.prepareStatement("select banks from ...
Before executing a Query you may choose to inform JDBC of the type and maximum length of the bind parameter. If not, based on the setXXX call, the maximum length of the type is taken, i.e., for a setString a 4k buffer is allocated. This API does not reduce the network round trip...