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  • PreparedStatement執行sql語句

    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    
    import org.junit.Test;
    
    import util.JdbcUtil;
    /**
     * PreparedStatement執行sql語句
     * @author APPle
     *
     */
    public class Demo1 {
    
        /**
         * 增加
         */
        @Test
        public void testInsert() {
            Connection conn = null;
            PreparedStatement stmt = null;
            try {
                //1.获取连接
                conn = JdbcUtil.getConnection();
                
                //2.准备预编译的sql
                String sql = "INSERT INTO student2(NAME,gender) VALUES(?,?)"; //?表示一个参数的占位符
                
                //3.执行预编译sql语句(检查语法)
                stmt = conn.prepareStatement(sql);
                
                //4.设置参数值
                /**
                 * 参数一: 参数位置  从1开始
                 */
                stmt.setString(1, "李四");
                stmt.setString(2, "男");
                
                //5.发送参数,执行sql
                int count = stmt.executeUpdate();
                
                System.out.println("影响了"+count+"行");
                
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException(e);
            } finally {
                JdbcUtil.close(conn, stmt);
            }
        }
        
        /**
         * 修改
         */
        @Test
        public void testUpdate() {
            Connection conn = null;
            PreparedStatement stmt = null;
            try {
                //1.获取连接
                conn = JdbcUtil.getConnection();
                
                //2.准备预编译的sql
                String sql = "UPDATE student2 SET NAME=? WHERE id=?"; //?表示一个参数的占位符
                
                //3.执行预编译sql语句(检查语法)
                stmt = conn.prepareStatement(sql);
                
                //4.设置参数值
                /**
                 * 参数一: 参数位置  从1开始
                 */
                stmt.setString(1, "王五");
                stmt.setInt(2, 9);
                
                //5.发送参数,执行sql
                int count = stmt.executeUpdate();
                
                System.out.println("影响了"+count+"行");
                
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException(e);
            } finally {
                JdbcUtil.close(conn, stmt);
            }
        }
        
        /**
         * 删除
         */
        @Test
        public void testDelete() {
            Connection conn = null;
            PreparedStatement stmt = null;
            try {
                //1.获取连接
                conn = JdbcUtil.getConnection();
                
                //2.准备预编译的sql
                String sql = "DELETE FROM student2 WHERE id=?"; //?表示一个参数的占位符
                
                //3.执行预编译sql语句(检查语法)
                stmt = conn.prepareStatement(sql);
                
                //4.设置参数值
                /**
                 * 参数一: 参数位置  从1开始
                 */
                stmt.setInt(1, 9);
                
                //5.发送参数,执行sql
                int count = stmt.executeUpdate();
                
                System.out.println("影响了"+count+"行");
                
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException(e);
            } finally {
                JdbcUtil.close(conn, stmt);
            }
        }
        
        /**
         * 查询
         */
        @Test
        public void testQuery() {
            Connection conn = null;
            PreparedStatement stmt = null;
            ResultSet rs = null;
            try {
                //1.获取连接
                conn = JdbcUtil.getConnection();
                
                //2.准备预编译的sql
                String sql = "SELECT * FROM student2"; 
                
                //3.预编译
                stmt = conn.prepareStatement(sql);
                
                //4.执行sql
                rs = stmt.executeQuery();
                
                //5.遍历rs
                while(rs.next()){
                    int id = rs.getInt("id");
                    String name = rs.getString("name");
                    String gender = rs.getString("gender");
                    System.out.println(id+","+name+","+gender);
                }
                
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException(e);
            } finally {
                //关闭资源
                JdbcUtil.close(conn,stmt,rs);
            }
        }
    }
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  • 原文地址:https://www.cnblogs.com/linst/p/5868412.html
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