JDBC 增删改查代码示例：使用预处理语句 (PreparedStatement)

下面是使用JDBC进行增删改查操作的具体代码实现，使用了预处理语句（PreparedStatement）：\n\n1. 导入必要的类：\njava\nimport java.sql.Connection;\nimport java.sql.DriverManager;\nimport java.sql.PreparedStatement;\nimport java.sql.ResultSet;\nimport java.sql.SQLException;\n\n\n2. 建立数据库连接：\njava\nConnection conn = null;\ntry {\n String url = "jdbc:mysql://localhost:3306/mydatabase";\n String username = "root";\n String password = "password";\n conn = DriverManager.getConnection(url, username, password);\n} catch (SQLException e) {\n e.printStackTrace();\n}\n\n\n3. 插入数据：\njava\nString insertQuery = "INSERT INTO table_name (column1, column2, ...) VALUES (?, ?, ...)";\ntry {\n PreparedStatement pstmt = conn.prepareStatement(insertQuery);\n pstmt.setString(1, value1);\n pstmt.setString(2, value2);\n // ...\n pstmt.executeUpdate();\n pstmt.close();\n} catch (SQLException e) {\n e.printStackTrace();\n}\n\n\n4. 更新数据：\njava\nString updateQuery = "UPDATE table_name SET column1 = ?, column2 = ?, ... WHERE condition";\ntry {\n PreparedStatement pstmt = conn.prepareStatement(updateQuery);\n pstmt.setString(1, newValue1);\n pstmt.setString(2, newValue2);\n // ...\n pstmt.executeUpdate();\n pstmt.close();\n} catch (SQLException e) {\n e.printStackTrace();\n}\n\n\n5. 删除数据：\njava\nString deleteQuery = "DELETE FROM table_name WHERE condition";\ntry {\n PreparedStatement pstmt = conn.prepareStatement(deleteQuery);\n // ...\n pstmt.executeUpdate();\n pstmt.close();\n} catch (SQLException e) {\n e.printStackTrace();\n}\n\n\n6. 查询数据：\njava\nString selectQuery = "SELECT column1, column2, ... FROM table_name WHERE condition";\ntry {\n PreparedStatement pstmt = conn.prepareStatement(selectQuery);\n // ...\n ResultSet rs = pstmt.executeQuery();\n while (rs.next()) {\n // 处理查询结果\n String value1 = rs.getString("column1");\n String value2 = rs.getString("column2");\n // ...\n }\n rs.close();\n pstmt.close();\n} catch (SQLException e) {\n e.printStackTrace();\n}\n\n\n7. 关闭数据库连接：\njava\ntry {\n if (conn != null) {\n conn.close();\n }\n} catch (SQLException e) {\n e.printStackTrace();\n}\n\n\n请注意，以上代码中的"table_name"需要替换为具体的表名，"column1, column2, ..."需要替换为具体的列名，"condition"需要替换为具体的条件。另外，需要根据实际情况修改数据库连接的URL、用户名和密码。