我無法將數據插入到我的 sqlite 表中。我想將變量插入列而不是固定數據Fixed data:"INSERT INTO DATOS (ID,NOMBRE,GRUPO,TUTOR) " + "VALUES (1, 'Paul', 32, 'California');";That i want:"INSERT INTO DATOS (ID,NOMBRE,GRUPO,TUTOR) " + "VALUES (variableID, variableName, variableNumber, variableCity);";我一直在閱讀文檔，但我無法將其弄出來，請您幫幫我。目前我設法創建數據庫并手動插入數據：package com.proyecto.demo;import java.sql.*;public class SQLiteJDBC {public static void main( String args[] ) { Connection c = null; Statement stmt = null; try { // Create the table Class.forName("org.sqlite.JDBC"); c = DriverManager.getConnection("jdbc:sqlite:test.db"); System.out.println("Paso 1: Base de datos creada"); stmt = c.createStatement(); String sql = "CREATE TABLE DATOS " + "(ID INT PRIMARY KEY NOT NULL," + " NOMBRE TEXT NOT NULL, " + " GRUPO TEXT NOT NULL, " + " TUTOR INT)"; stmt.executeUpdate(sql); stmt.close(); c.close(); } catch ( Exception e ) { System.err.println( e.getClass().getName() + ": " + e.getMessage() ); System.exit(0); } try { // Insert date to the table (here is where i have problems) System.out.println("Paso 2: Conectar Base de datos"); Class.forName("org.sqlite.JDBC"); c = DriverManager.getConnection("jdbc:sqlite:test.db"); c.setAutoCommit(false); System.out.println("Opened database successfully"); stmt = c.createStatement(); String sql = "INSERT INTO DATOS (ID,NOMBRE,GRUPO,TUTOR) " + "VALUES (1, 'Paul', 32, 'California');"; stmt.executeUpdate(sql); stmt.close(); c.commit(); c.close(); } catch ( Exception e ) { System.err.println( e.getClass().getName() + ": " + e.getMessage() ); System.exit(0); } System.out.println("All inserted!"); }}PD：一位用戶建議我使用 SQL 腳本來執行我的任務，但另一位用戶告訴我使用“preparedstatement”。哪個更好？
1 回答
慕婉清6462132
TA貢獻1804條經驗 獲得超2個贊
您必須使用PreparedStatement。此外，強烈建議在 Java-8 之后將數據庫連接視為AutoClosables。您可以閱讀try-with-resources 聲明以了解如何執行此操作。最后，不要使用Exception類來捕獲異常。捕獲大多數情況下您會遇到的那種異常，在您的情況下是SQLException.
以下是上述內容的完整示例：
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;
public class SQLiteSample {
private static final String URL = "jdbc:sqlite:data.db";
public static void main(String[] args) {
createDb();
createTable();
insertPerson("Thomas", 15);
insertPerson("Walter", 32);
}
private static void insertPerson(String name, int age) {
final String SQL = "INSERT INTO persons VALUES(?,?)";
try (Connection con = getConnection(); PreparedStatement ps = con.prepareStatement(SQL);) {
ps.setString(1, name); // First question mark will be replaced by name variable - String;
ps.setInt(2, age); // Second question mark will be replaced by name variable - Integer;
ps.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
}
}
private static void createTable() {
final String SQL = "CREATE TABLE IF NOT EXISTS persons (name TEXT, age INTEGER);";
// This SQL Query is not "dynamic". Columns are static, so no need to use
// PreparedStatement.
try (Connection con = getConnection(); Statement statement = con.createStatement();) {
statement.executeUpdate(SQL);
} catch (SQLException e) {
e.printStackTrace();
}
}
private static void createDb() {
try (Connection conn = getConnection()) {
if (conn != null) {
conn.getMetaData();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
public static Connection getConnection() throws SQLException {
return DriverManager.getConnection(URL);
}
}
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