為了保證數(shù)據(jù)的一致性、完整性
比如100條數(shù)據(jù)颁督，插入數(shù)據(jù)庫
前50條成功插入渣触，后面50沒有成功插入，這就屬于不完整數(shù)據(jù)
所以我們要用事務(wù)管理來解決

//      設(shè)置為false蟋字，就不會(huì)自動(dòng)提交到數(shù)據(jù)庫稿蹲，比如前50條數(shù)據(jù)通過，后面50不通過鹊奖，這樣也不會(huì)進(jìn)入數(shù)據(jù)庫
conn.setAutoCommit(false);

但是苛聘，使用conn.setAutoCommit(false);要注意數(shù)據(jù)庫死鎖

所以
（設(shè)定setAutoCommit(false)沒有在catch中進(jìn)行Connection的rollBack操作，操作的表就會(huì)被鎖住忠聚，造成數(shù)據(jù)庫死鎖）：  
try {
            conn = getConnection();
            conn.setAutoCommit(false);

            insertUserData(conn);
            insertAddressData(conn);
            
            conn.commit();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            System.out.println("=====捕獲到sql異常======");
            e.printStackTrace();
            try {
                conn.rollback();
                System.out.println("======事務(wù)回滾成功=====");
            } catch (Exception e2) {
                // TODO: handle exception
                e2.printStackTrace(); 
            }
注意:
setAutoCommit在try里面
 conn.rollback();一定要在catch里面
 //  conn.rollback();是數(shù)據(jù)回滾设哗，是數(shù)據(jù)庫中事物的執(zhí)行，有一條插入失敗两蟀，所有的都不插入熬拒，數(shù)據(jù)庫回滾到操作之前的樣子

代碼

package com.chenzebin.jdbc;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

public class TransactionTest {

    public static Connection getConnection() {
        Connection conn = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/jsp_db", "root", "");

        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
        return conn;
    }

    public static void insertUserData(Connection conn) throws SQLException {

        String sql = "insert into tbl_user(id,name,password,email)" + "values(10,'Tom','123456','tom@gmail.com')";
        Statement st = conn.createStatement();
        int count = st.executeUpdate(sql);
        System.out.println("向用戶表插入" + count + "條記錄");

    }

    public static void insertAddressData(Connection conn) throws SQLException {
        String sql = "insert into tbl_address(id,city,country,user_id)" + "values(1,'shanghai','china','10')";
        Statement st = conn.createStatement();
        int count = st.executeUpdate(sql);
        System.out.println("向地址表中插入了" + count + "條記錄");

    }

    public static void main(String[] args) {
        Connection conn = null;
        try {
            conn = getConnection();
            conn.setAutoCommit(false);

            insertUserData(conn);
            insertAddressData(conn);
            
            conn.commit();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            System.out.println("=====捕獲到sql異常======");
            e.printStackTrace();
            try {
                conn.rollback();
                System.out.println("======事務(wù)回滾成功=====");
            } catch (Exception e2) {
                // TODO: handle exception
                e2.printStackTrace(); 
            }
        }finally {
            try {
                if(conn != null) {
                    conn.close();
                }
            } catch (Exception e3) {
                // TODO: handle exception
                e3.printStackTrace();
            }
        }

    }

}