使用PreparedStatement接口实现增，删，改操作

1. PreparedStatement接口引入

PreparedStatement是Statement的子接口，属于预处理操作，与直接使用Statement不同的是，PreparedStatement在操作时，是先在数据表中准备好了一条SQL语句，但是此SQL语句的具体内容暂时不设置，而是之后再进行设置。

以后开发一般用PreparedStatement，不用Statement

2. 使用PreparedStatement接口实现添加数据操作

3. 使用PreparedStatement接口实现更新数据操作

4. 使用PreparedStatement接口实现删除数据操作

TestInsert.java

package com.andrew.jdbc.chap04;

import java.sql.Connection;
import java.sql.PreparedStatement;

import com.andrew.jdbc.model.Book;
import com.andrew.jdbc.util.DbUtil;

public class TestInsert {
    private static DbUtil dbUtil = new DbUtil();
    private static int addBook(Book book) throws Exception {
        Connection connection = dbUtil.getConnection(); // 获取连接
        String sql = "insert into t_book values(null,?,?,?,?)";
        PreparedStatement preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setString(1, book.getBookName());
        preparedStatement.setFloat(2, book.getPrice());
        preparedStatement.setString(3, book.getAuthor());
        preparedStatement.setInt(4, book.getBookTypeId());
        int result = preparedStatement.executeUpdate();
        dbUtil.close(preparedStatement, connection);
        return result;
    }
    public static void main(String[] args) throws Exception {
        Book book = new Book("Java学习2", 1, "学习2", 1);
        int result = addBook(book);
        if (result == 1) {
            System.out.println("添加成功！");
        } else {
            System.out.println("添加失败！");
        }
    }
}

添加成功！

TestUpdate.java

package com.andrew.jdbc.chap04;

import java.sql.Connection;
import java.sql.PreparedStatement;

import com.andrew.jdbc.model.Book;
import com.andrew.jdbc.util.DbUtil;

public class TestUpdate {
    private static DbUtil dbUtil = new DbUtil();
    private static int updateBook(Book book) throws Exception {
        Connection connection = dbUtil.getConnection();
        String sql = "update t_book set bookName=?,price=?,author=?,bookTypeId=? where id=?";
        PreparedStatement preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setString(1, book.getBookName());
        preparedStatement.setFloat(2, book.getPrice());
        preparedStatement.setString(3, book.getAuthor());
        preparedStatement.setInt(4, book.getBookTypeId());
        preparedStatement.setInt(5, book.getId());
        int result = preparedStatement.executeUpdate();
        dbUtil.close(preparedStatement, connection);
        return result;
    }
    public static void main(String[] args) throws Exception {
        Book book = new Book(4, "K2", 2, "K", 2);
        int result = updateBook(book);
        if (result == 1) {
            System.out.println("更新成功！");
        } else {
            System.out.println("更新失败！");
        }
    }
}

更新成功！

TestDelete.java

package com.andrew.jdbc.chap04;

import java.sql.Connection;
import java.sql.PreparedStatement;

import com.andrew.jdbc.util.DbUtil;

public class TestDelete {
    private static DbUtil dbUtil = new DbUtil();
    private static int deleteBook(int id) throws Exception {
        Connection connection = dbUtil.getConnection();
        String sql = "delete from t_book where id=?";
        PreparedStatement preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setInt(4, id);
        int result = preparedStatement.executeUpdate();
        dbUtil.close(preparedStatement, connection);
        return result;
    }
    public static void main(String[] args) throws Exception {
        int result = deleteBook(12);
        if (result == 1) {
            System.out.println("删除成功！");
        } else {
            System.out.println("删除失败！");
        }
    }
}

删除成功！