JDBC的进阶知识和语法[以mysql为例作Demo](二)

三丨继Batch之Transaction Google翻译

缘由：如A转账予B，那么JDBC至少要操作2条UPDATE语句(A减B加)，Transaction就是为了保证这两条语句必须同时执行成功或者同时执行失败。

package com.qsuron.test;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;

import com.qsuron.util.DB;

public class Test6 {
	public static void main(String[] args) throws SQLException {
		Connection conn = DB.getConnection();
		Statement stmt = DB.getStatement(conn);
		try {
			conn.setAutoCommit(false);
			//将自动提交设置为false，将多条语句积累到一起
			stmt.addBatch("insert into student values ('1213400135','1','Q');");
			stmt.addBatch("insert into student values ('1213400136','1','Q');");
			stmt.addBatch("insert into student values ('1213400134','1','Q');");
			stmt.executeBatch();
			conn.commit();
			//执行
			conn.setAutoCommit(true);
			//重置自动提交
		} catch (Exception e) {
			//如果抓到异常就现场恢复
			if(conn!=null){
				conn.rollback();
				//数据回滚
				System.out.println("Exception:Rollback!");
				conn.setAutoCommit(true);
			}
		}
		DB.close();
	}
}

四丨ResultSet 结果集

1.前后滚动机制

package com.qsuron.test;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import com.qsuron.util.DB;

public class Test7 {
	public static void main(String[] args) throws SQLException {
		Connection conn = DB.getConnection();
		Statement stmt = DB.getStatement(conn,ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);
		ResultSet rs = DB.query(stmt,"select * from student order by id;");
		rs.last();
		System.out.println("当前行数:"+rs.getRow());
		System.out.println(rs.getString(1));
		rs.previous();
		System.out.println(rs.getString(1));
		rs.absolute(7);
		System.out.println(rs.getString(1));
		DB.close();
	}
}

2.JDBC之ResultSet对象-注意事项(点击前往)

转载请注明出处:blog.csdn.net/qsuron 小树博客(qsuron)