Java jdbc 操作數據庫詳解
阿新 • • 發佈：2018-09-08
drive stat man println span 都是 sets for 連接 
原文地址https://www.cnblogs.com/huguodong/p/5910859.html
JDBC（Java Data Base Connectivity,java數據庫連接）是一種用於執行SQL語句的Java API，可以為多種關系數據庫提供統一訪問，它由一組用java語言編寫的類和接口組成。
有了JDBC，向各種關系數據發送SQL語句就是一件很容易的事。換言之，有了JDBC API，就不必為訪問Sybase數據庫專門寫一個程序，為訪問Oracle數據庫又專門寫一個程序，或為訪問Informix數據庫又編寫另一個程序等等，程序員只需用JDBC API寫一個程序就夠了，它可向相應數據庫發送SQL調用。
/** * JDBC:文件驅動 * 1.引入jar包 ojdbc.jar 在工程的目錄下創建一個lib文件夾用來存放jar包 * 在ojdbc14.jar這個文件上右鍵==>build Path==> add to build Path * 2.編寫DB類 * a.加載驅動 * b.設置參數url user pwd * c.連接數據庫 * d.編寫sql語句 * e.編譯sql語句 * f.如果存在條件 * 設置條件後執行sql語句，如果沒有條件直接執行sql語句 g.如果是增刪改 那麽sql執行結束 如果是查詢，遍歷結果集 f.關閉數據庫 * * * */
二、初始化
1.配置連接：在引入了ojdbc14.jar包之後，我們需要使用Class.forName方法加載驅動，然後通過DriverManager.getConnection來獲取連接
// 初始化
public void init() {
// 不同的數據庫有不同的驅動
String driverName = "oracle.jdbc.driver.OracleDriver";
String url = "jdbc:oracle:thin:@192.168.1.150:1521:XE";
String user = "hr";
String password = "123456";
try {
// 加載驅動
Class.forName(driverName);
// 設置 配置數據
// 1.url(數據看服務器的ip地址 數據庫服務端口號 數據庫實例)
// 2.user
// 3.password
conn = DriverManager.getConnection(url, user, password);
// 開始連接數據庫
System.out.println("數據庫連接成功..");
} catch (ClassNotFoundException e) {
// TODO 自動生成的 catch 塊
e.printStackTrace();
} catch (SQLException e) {
// TODO 自動生成的 catch 塊
e.printStackTrace();
}
}
2.初始化
Connection conn = null;
public static void main(String[] args) {
DB db = new DB();
db.init();
}
三、操作
如果我們需要操作數據，就需要一個容器來保存它，這裏我們可以用javabean來保存他們。
public class Student {
private Integer id;
private String name;
private Integer age;
private Integer agestart;
private Integer ageend;
public Integer getAgestart() {
return agestart;
}
public void setAgestart(Integer agestart) {
this.agestart = agestart;
}
public Integer getAgeend() {
return ageend;
}
public void setAgeend(Integer ageend) {
this.ageend = ageend;
}
public Student() {
// TODO 自動生成的構造函數存根
}
public Student(Integer id, String name, Integer age) {
super();
this.id = id;
this.name = name;
this.age = age;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
1.簡單的查詢
public List<Student> select() throws SQLException {
List<Student> list = new ArrayList<Student>();
// *查詢
// 創建sql語句
String sqlString = "select * from student";
// 編譯sql語句
// 執行查詢
pst = conn.prepareStatement(sqlString);
rSet = pst.executeQuery();
// 遍歷結果
Student student = null;
while (rSet.next()) {
// System.out.print(rSet.getInt(1) + "\t");
// System.out.print(rSet.getString(2) + "\t");
// System.out.print(rSet.getInt(3) + "\t");
// System.out.print("\n");
student = new Student();
student.setId(rSet.getInt(1));
student.setName(rSet.getString(2));
student.setAge(rSet.getInt(3));
list.add(student);
}
return list;
}
List<Student> students = null;
students = db.select();
for (int i = 0; i < students.size(); i++) {
System.out.print(students.get(i).getId() + "\t");
System.out.print(students.get(i).getName() + "\t");
System.out.print(students.get(i).getAge());
System.out.println();
}
結果：
2.條件查詢
public List<Student> selectByStu(int age) throws SQLException {
List<Student> students = new ArrayList<Student>();
String sql = "select * from student where sage=? ";
pst = conn.prepareStatement(sql);
// 設置條件(相對於條件查詢)
pst.setInt(1, age);
rSet = pst.executeQuery();
Student student = null;
while (rSet.next()) {
student = new Student();
student.setId(rSet.getInt(1));
student.setName(rSet.getString(2));
student.setAge(rSet.getInt(3));
students.add(student);
}
return students;
}
students = db.selectByStu(20);
for (int i = 0; i < students.size(); i++) {
System.out.print(students.get(i).getId() + "\t");
System.out.print(students.get(i).getName() + "\t");
System.out.print(students.get(i).getAge());
System.out.println();
}
結果：
3.多個條件查詢
public List<Student> selectByCondition(Student e) throws SQLException {
List<Student> students = new ArrayList<Student>();
String sql = "select * from student where sage>? and sage<? ";
pst = conn.prepareStatement(sql);
pst.setInt(1, e.getAgestart());
pst.setInt(2, e.getAgeend());
rSet = pst.executeQuery();
Student student = null;
while (rSet.next()) {
student = new Student();
student.setId(rSet.getInt(1));
student.setName(rSet.getString(2));
student.setAge(rSet.getInt(3));
students.add(student);
}
return students;
}
Student stu = new Student();
stu.setAgestart(20);
stu.setAgeend(22);
students = db.selectByCondition(stu);
for (int i = 0; i < students.size(); i++) {
System.out.print(students.get(i).getId() + "\t");
System.out.print(students.get(i).getName() + "\t");
System.out.print(students.get(i).getAge());
System.out.println();
}
4.添加數據
public void save(Student student) throws SQLException {
String sql = "insert into student values (?,?,?,null,null,null,null,null)";
pst = conn.prepareStatement(sql);
pst.setInt(1, student.getId());
pst.setString(2, student.getName());
pst.setInt(3, student.getAge());
pst.executeUpdate();
System.out.println("添加成功");
}
5.更新數據
public void update(Student student) throws SQLException {
String sql = "update student set sage=? where sid=?";
pst = conn.prepareStatement(sql);
pst.setInt(1, student.getAge());
pst.setInt(2, student.getId());
pst.executeUpdate();
System.out.println("更新成功");
}
6.刪除數據
public void delete(Integer id) throws SQLException {
String sql = "delete student where sid=?";
pst = conn.prepareStatement(sql);
pst.setInt(1, id);
pst.executeUpdate();
System.out.println("刪除成功");
}
7.分頁
public List<Student> findByPage(int start, int end) throws SQLException {
List<Student> students = new ArrayList<Student>();
String sql = "select s_.* from(select s.*,rownum rn from (select * from student order by sid) s where rownum<=?) s_ where rn>?";
pst = conn.prepareStatement(sql);
pst.setInt(1, end);
pst.setInt(2, start);
rSet = pst.executeQuery();
Student student = null;
while (rSet.next()) {
student = new Student();
student.setId(rSet.getInt(1));
student.setName(rSet.getString(2));
student.setAge(rSet.getInt(3));
students.add(student);
}
return students;
}
四、筆記
package com.hgd.study.JDBC;
import java.net.CookieHandler;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class DB {
Connection conn = null;
PreparedStatement pst;
ResultSet rSet;
public static void main(String[] args) {
DB db = new DB();
List<Student> students = null;
try {
db.initConn();
//students = db.select();
//students = db.selectByStu(20);
Student stu = new Student();
stu.setAgestart(20);
stu.setAgeend(22);
students = db.selectByCondition(stu);
for (int i = 0; i < students.size(); i++) {
System.out.print(students.get(i).getId() + "\t");
System.out.print(students.get(i).getName() + "\t");
System.out.print(students.get(i).getAge());
System.out.println();
}
// Student stu = new Student(123, "李四", 23);
// db.save(stu);
// Student stu=new Student();
// stu.setId(10003);
// stu.setAge(23);
// db.update(stu);
// db.delete(123);
/*
* 事物： 1.原子性：每一個事物都是一個單獨的操作 2.一致性：事物中的所有操作，只要成功全部成功，一旦失敗全部失敗
* 3.隔離性：事物中的操作之間沒不會產生影響他們都是一個獨立的操作 4.持久性：事物一旦成功將被永久寫入數據庫
*/
// conn.setAutoCommit(false);// 設置自動事物為false
// conn.setSavepoint();// 設置事物的回滾點
// conn.rollback();//事物回滾
// conn.commit();//事物提交
// db.setAutoCommit(false);
// db.setSavepoint();
// Student stu = new Student();
// stu.setId(10003);
// stu.setAge(0);
// db.update(stu);
// if (stu.getAge() <= 0) {
// db.rollback();
// System.out.println("取消了操作");
// } else {
// db.commit();
// }
} catch (Exception e) {
// TODO 自動生成的 catch 塊
e.printStackTrace();
} finally {
try {
db.close();
} catch (Exception e) {
// TODO 自動生成的 catch 塊
e.printStackTrace();
}
}
}
// 初始化
public void init() {
// 不同的數據庫有不同的驅動
String driverName = "oracle.jdbc.driver.OracleDriver";
String url = "jdbc:oracle:thin:@192.168.1.150:1521:XE";
String user = "hr";
String password = "123456";
try {
// 加載驅動
Class.forName(driverName);
// 設置 配置數據
// 1.url(數據看服務器的ip地址 數據庫服務端口號 數據庫實例)
// 2.user
// 3.password
conn = DriverManager.getConnection(url, user, password);
// 開始連接數據庫
System.out.println("數據庫連接成功..");
} catch (ClassNotFoundException e) {
// TODO 自動生成的 catch 塊
e.printStackTrace();
} catch (SQLException e) {
// TODO 自動生成的 catch 塊
e.printStackTrace();
}
}
public void initConn() throws Exception {
if (conn == null || conn.isClosed()) {
this.init();
}
}
public void close() throws Exception {
if (conn != null && !conn.isClosed()) {
conn.close();
conn = null;
}
}
public void setAutoCommit(boolean fals) throws Exception {
if (conn != null && !conn.isClosed()) {
conn.setAutoCommit(fals);
}
}
public void setSavepoint() throws Exception {
if (conn != null && !conn.isClosed()) {
conn.setSavepoint();
}
}
public void rollback() throws Exception {
if (conn != null && !conn.isClosed()) {
conn.rollback();
}
}
public void commit() throws Exception {
if (conn != null && !conn.isClosed()) {
conn.commit();
}
}
// 簡單查詢
public List<Student> select() throws SQLException {
List<Student> list = new ArrayList<Student>();
// *查詢
// 創建sql語句
String sqlString = "select * from student";
// 編譯sql語句
// 執行查詢
pst = conn.prepareStatement(sqlString);
rSet = pst.executeQuery();
// 遍歷結果
Student student = null;
while (rSet.next()) {
// System.out.print(rSet.getInt(1) + "\t");
// System.out.print(rSet.getString(2) + "\t");
// System.out.print(rSet.getInt(3) + "\t");
// System.out.print("\n");
student = new Student();
student.setId(rSet.getInt(1));
student.setName(rSet.getString(2));
student.setAge(rSet.getInt(3));
list.add(student);
}
return list;
}
// 條件查詢
public List<Student> selectByStu(int age) throws SQLException {
List<Student> students = new ArrayList<Student>();
String sql = "select * from student where sage=? ";
pst = conn.prepareStatement(sql);
// 設置條件(相對於條件查詢)
pst.setInt(1, age);
rSet = pst.executeQuery();
Student student = null;
while (rSet.next()) {
student = new Student();
student.setId(rSet.getInt(1));
student.setName(rSet.getString(2));
student.setAge(rSet.getInt(3));
students.add(student);
}
return students;
}
// 多個條件值查詢
public List<Student> selectByCondition(Student e) throws SQLException {
List<Student> students = new ArrayList<Student>();
String sql = "select * from student where sage>? and sage<? ";
pst = conn.prepareStatement(sql);
pst.setInt(1, e.getAgestart());
pst.setInt(2, e.getAgeend());
rSet = pst.executeQuery();
Student student = null;
while (rSet.next()) {
student = new Student();
student.setId(rSet.getInt(1));
student.setName(rSet.getString(2));
student.setAge(rSet.getInt(3));
students.add(student);
}
return students;
}
// 添加數據
public void save(Student student) throws SQLException {
String sql = "insert into student values (?,?,?,null,null,null,null,null)";
pst = conn.prepareStatement(sql);
pst.setInt(1, student.getId());
pst.setString(2, student.getName());
pst.setInt(3, student.getAge());
pst.executeUpdate();
System.out.println("添加成功");
}
// 更新數據
public void update(Student student) throws SQLException {
String sql = "update student set sage=? where sid=?";
pst = conn.prepareStatement(sql);
pst.setInt(1, student.getAge());
pst.setInt(2, student.getId());
pst.executeUpdate();
System.out.println("更新成功");
}
// 刪除數據
public void delete(Integer id) throws SQLException {
String sql = "delete student where sid=?";
pst = conn.prepareStatement(sql);
pst.setInt(1, id);
pst.executeUpdate();
System.out.println("刪除成功");
}
// 分頁
public List<Student> findByPage(int start, int end) throws SQLException {
List<Student> students = new ArrayList<Student>();
String sql = "select s_.* from(select s.*,rownum rn from (select * from student order by sid) s where rownum<=?) s_ where rn>?";
pst = conn.prepareStatement(sql);
pst.setInt(1, end);
pst.setInt(2, start);
rSet = pst.executeQuery();
Student student = null;
while (rSet.next()) {
student = new Student();
student.setId(rSet.getInt(1));
student.setName(rSet.getString(2));
student.setAge(rSet.getInt(3));
students.add(student);
}
return students;
}
}
Java jdbc 操作數據庫詳解