PreparedStatement執行sql語句
时间：2021-07-01 10:21:17
帮助过：2人阅读
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);
}
}
}
PreparedStatement執行sql語句
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