本文最后更新于：2023年8月24日 晚上
准备操作
下载 jar 包：mysql-connector-java
搜索jar包：https://mvnrepository.com/
整体步骤：
- 导入jar包
- 使用
Class.forName("com.mysql.cj.jdbc.Driver")注册驱动（8.0）
- 获取conn对象，并使用
prepareStatement装入sql语句
- 使用pre对应方法执行
封装连接工具类
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| public class getConn {
private static String url, user, pwd;
private static Connection conn;
static {
url = "jdbc:mysql://XXX.XXX.XXX.XXX:XXXX/FSAN?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8";
user = "root";
pwd = "FSAN";
}
public Connection getConn() {
try {
Class.forName("com.mysql.cj.jdbc.Driver");
conn = DriverManager.getConnection(url, user, pwd);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
}
|
CRUD 操作
添加数据
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| public String addData(loginUser loginUser) {
try {
pre = conn.prepareStatement("insert into loginUser(username,password) VALUES (?,?)");
pre.setString(1, loginUser.getUsername());
pre.setString(2, loginUser.getPassword());
if (pre.executeUpdate() != 0) {
return "添加成功！";
} else {
return "添加失败！";
}
} catch (SQLException e) {
e.printStackTrace();
}
return "出现未知错误！";
}
|
修改数据
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| public String editData(loginUser loginUser) {
try {
pre = conn.prepareStatement("update loginUser set username=?,password=? where id=?");
pre.setString(1, loginUser.getUsername());
pre.setString(2, loginUser.getPassword());
pre.setInt(3, loginUser.getId());
if (pre.executeUpdate() != 0) {
return "修改成功！";
} else {
return "修改失败！";
}
} catch (SQLException e) {
e.printStackTrace();
}
return "出现未知错误！";
}
|
删除操作
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| public String delDataById(int id) {
try {
pre = conn.prepareStatement("delete from loginUser where id=?");
pre.setInt(1, id);
if (pre.executeUpdate() != 0) return "删除成功！";
return "id不存在！";
} catch (SQLException e) {
e.printStackTrace();
}
return "出现未知错误！";
}
|
查询操作
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| public ArrayList<loginUser> getAllData() {
try {
pre = conn.prepareStatement("select * from loginUser");
ResultSet result = pre.executeQuery();
while (result.next()) {
list.add(new loginUser(result.getInt("id"), result.getString("username"), result.getString("password")));
}
} catch (SQLException e) {
e.printStackTrace();
}
return list;
}
|
完整DB
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| public class JDBCAbout {
private static Connection conn;
private static PreparedStatement pre;
private static ArrayList<loginUser> list;
private static loginUser loginUser;
static {
conn = new getConn().getConn();
list = new ArrayList<>();
}
public ArrayList<loginUser> getAllData() {
try {
pre = conn.prepareStatement("select * from loginUser");
ResultSet result = pre.executeQuery();
while (result.next()) {
list.add(new loginUser(result.getInt("id"), result.getString("username"), result.getString("password")));
}
} catch (SQLException e) {
e.printStackTrace();
}
return list;
}
public String delDataById(int id) {
try {
pre = conn.prepareStatement("delete from loginUser where id=?");
pre.setInt(1, id);
if (pre.executeUpdate() != 0) return "删除成功！";
return "id不存在！";
} catch (SQLException e) {
e.printStackTrace();
}
return "出现未知错误！";
}
public String addData(loginUser loginUser) {
try {
pre = conn.prepareStatement("insert into loginUser(username,password) VALUES (?,?)");
pre.setString(1, loginUser.getUsername());
pre.setString(2, loginUser.getPassword());
if (pre.executeUpdate() != 0) {
return "添加成功！";
} else {
return "添加失败！";
}
} catch (SQLException e) {
e.printStackTrace();
}
return "出现未知错误！";
}
public String editData(loginUser loginUser) {
try {
pre = conn.prepareStatement("update loginUser set username=?,password=? where id=?");
pre.setString(1, loginUser.getUsername());
pre.setString(2, loginUser.getPassword());
pre.setInt(3, loginUser.getId());
if (pre.executeUpdate() != 0) {
return "修改成功！";
} else {
return "修改失败！";
}
} catch (SQLException e) {
e.printStackTrace();
}
return "出现未知错误！";
}
private void closeAll(Connection conn, PreparedStatement pre) {
try {
if (conn != null) {
conn.close();
}
if (pre != null) {
pre.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
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