crud.java

各种数据保存：字符型

package cn.itcast.jdbc;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;

public class CRUD {

	/**
	 * @param args
	 * @throws Exception
	 */
	public static void main(String[] args) throws Exception {
		// create();
		read("as' or 1 or '");
		// upate();
		// delete();
		// read();
	}

	static void delete() throws Exception {
		String sql = "delete from user where id=2";
		cdu(sql);
	}

	static void create() throws Exception {
		String sql = "insert into user(name, age) values('name1', 23)";
		cdu(sql);
	}

	static void upate() throws Exception {
		String sql = "update user set name='new name' where id=1";
		cdu(sql);
	}

	static void cdu(String sql) throws Exception {
		Connection conn = null;
		Statement st = null;
		ResultSet rs = null;
		try {
			conn = JdbcUtils.getConnection();
			st = conn.createStatement();
			int i = st.executeUpdate(sql);
			System.out.println("i=" + i);
		} finally {
			JdbcUtils.realse(rs, st, conn);
		}
	}

	static void read(String name) throws Exception {
		Connection conn = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		try {
			conn = JdbcUtils.getConnection();
			String sql = "select id, name, age from user where name='" + name
					+ "'";
			sql = "select id, name, age from user where name=?";
			System.out.println("sql:" + sql);
			// st = conn.createStatement();
			ps = conn.prepareStatement(sql);
			ps.setString(1, name);

			// rs = st.executeQuery(sql);
			rs = ps.executeQuery();
			while (rs.next()) {
				System.out.print(rs.getInt("id") + "\t");
				System.out.print(rs.getString("name") + "\t");
				System.out.print(rs.getInt("age"));
				System.out.println();
			}
		} finally {
			JdbcUtils.realse(rs, ps, conn);
		}
	}

}