基于Java对数据库表中的数据进行CRUD操作

CRUD增删改查(insert,delete,update,select)
CRUD操作部分

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.swing.text.StyledEditorKit.BoldAction;
import com.mysql.jdbc.jdbc2.optional.PreparedStatementWrapper;
public class UserCRUD {
	private Connection conn;
	private boolean insert(String username, String password) throws ClassNotFoundException, SQLException {
		PreparedStatement ps = null;
		try {
			conn=DBUtils.getConn();
			String sql = "insert into tbuser(username,password) values(?,?)";
			ps = conn.prepareStatement(sql);
			ps.setString(1, username);
			ps.setString(2, password);
			// 执行
			int i = ps.executeUpdate();
			return i > 0;
		} finally {
			DBUtils.close(null, ps, conn);
		}
	}

	private boolean update(int id, String password) throws ClassNotFoundException, SQLException {
		PreparedStatement ps = null;
		try {
			conn=DBUtils.getConn();
			String sql = "update tbuser set password=? where id=?";
			ps = conn.prepareStatement(sql);
			ps.setInt(1, id);
			ps.setString(2, password);
			// 执行
			int i = ps.executeUpdate();
			return i > 0;
		} finally {
			DBUtils.close(null, ps, conn);
		}

	}

	private boolean delete(int id) throws ClassNotFoundException, SQLException {
		PreparedStatement ps = null;
		try {
			conn=DBUtils.getConn();
			String sql = "delete from tbuser where id=?";
			ps = conn.prepareStatement(sql);
			ps.setInt(1, id);
			// 执行
			int i = ps.executeUpdate();
			return i > 0;
		} finally {
			DBUtils.close(null, ps, conn);
		}

	}

	public Map<String, Object> selectOne(String username) throws SQLException {
		// 声明map作为返回值
		Map<String, Object> map = new HashMap<String, Object>();
		String sql = "select * from tbuser where username=?";
		PreparedStatement ps = null;
		ResultSet rs = null;
		try {
			conn=DBUtils.getConn();
			ps = conn.prepareStatement(sql);
			ps.setString(1, username);
			rs = ps.executeQuery();
			if (rs.next()) {
				// 根据列的标签（默认列名，如有设置别名，则表骗为别名）获取列值
				int id = rs.getInt("id");
				String name = rs.getString("username");
				String pwd = rs.getString("password");
				//将获取的数据添加到集合
				map.put("id", id);
				map.put("username", name);
				map.put("password", pwd);
			}
		} finally {
			DBUtils.close(rs, ps, conn);
		}

		return map;
	}

	public List<Map<String, Object>> selectAll() throws SQLException {
		List<Map<String, Object>> list=new ArrayList<Map<String,Object>>();
		String sql = "select * from tbuser";
		PreparedStatement ps = null;
		ResultSet rs = null;
		try {
			conn=DBUtils.getConn();
			ps = conn.prepareStatement(sql);
			rs = ps.executeQuery();
			while (rs.next()) {
				Map<String, Object> map=new HashMap<>();
				int id = rs.getInt("id");
				String name = rs.getString("username");
				String pwd = rs.getString("password");
				//将获取的数据添加到集合
				map.put("id", id);
				map.put("username", name);
				map.put("password", pwd);
				list.add(map);
			}
		} finally {
			DBUtils.close(rs, ps, conn);
		}

		return list;

	}

	public static void main(String[] args) throws ClassNotFoundException, SQLException {
		UserCRUD crud = new UserCRUD();
		// boolean f = crud.insert("softeem123", "123softeem");
		// boolean f = crud.delete(7);
		// boolean f = crud.update(6,"11111");
		//p<String, Object> f = crud.selectOne("softeem");
		List<Map<String, Object>> list =crud.selectAll();
		//System.out.println("执行结果为：" + f);
	    System.out.println("执行结果为：" + list);
	}

}

工具类，JDBC基本封装

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mysql.jdbc.Statement;

/**
 * 数据库工具类 将访问数据库的公共代码抽取： 1、加载驱动 2、获取链接 6、关闭资源
 * 
 * @author lenovo
 *
 */
public class DBUtils {
	/** 驱动类路径 */
	private static final String DRIVER_CLASS = "com.mysql.jdbc.Driver";
	/** url地址 */
	private static final String URL = "jdbc:mysql://localhost:3306/mydb2";
	/** 数据库服务器登录用户名 */
	private static final String USER = "root";
	/** 数据库服务器登录密码 */
	private static final String PASSWORD = "123456";

	static {
		try {
			Class.forName(DRIVER_CLASS);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}

	/**
	 * 获取数据库链接对象
	 * 
	 * @return
	 */
	public static synchronized Connection getConn() {
		try {
			return DriverManager.getConnection(URL, USER, PASSWORD);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 关闭资源
	 * @param rs
	 * @param ps
	 * @param conn
	 */
	public static void close(ResultSet rs, PreparedStatement ps, Connection conn) {
		try {
			if (rs != null)
				rs.close();
			if (ps != null)
				ps.close();
			if (conn != null)
				conn.close();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
}