3.使用jdbc完成 crud

JdbcUtils.java

package utils;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.Properties;public class JdbcUtils {private static Properties config = new Properties();static{try {config.load(JdbcUtils.class.getClassLoader().getResourceAsStream("db.properties"));Class.forName(config.getProperty("driver"));} catch (Exception e) {throw new ExceptionInInitializerError(e);}}public static Connection getConnection()throws Exception{return DriverManager.getConnection(config.getProperty("url"),config.getProperty("username"),config.getProperty("password"));}public static void release(Connection conn,Statement st,ResultSet rs) {if(rs != null){try {rs.close();} catch (Exception e) {e.printStackTrace();}rs = null;}if(st != null){try {st.close();} catch (Exception e) {e.printStackTrace();}st = null;}if(conn!=null){try {conn.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}conn = null;}}}

db.properties

url=jdbc:mysql://localhost:3306/mydb2driver = com.mysql.jdbc.Driverusername = rootpassword = root

Users.java

package domain;import java.sql.Date;public class Users {private int id;String username;String password;Date birthday;Date entry_date;String job;String salary;String ersume;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public Date getBirthday() {return birthday;}public void setBirthday(Date birthday) {this.birthday = birthday;}public Date getEntry_date() {return entry_date;}public void setEntry_date(Date entry_date) {this.entry_date = entry_date;}public String getJob() {return job;}public void setJob(String job) {this.job = job;}public String getSalary() {return salary;}public void setSalary(String salary) {this.salary = salary;}public String getErsume() {return ersume;}public void setErsume(String ersume) {this.ersume = ersume;}}

Sql2.java

package mysql2;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.ArrayList;import java.util.List;import org.junit.Test;import domain.Users;import utils.JdbcUtils;public class Sql2 {public static void main(String[] args) {// TODO Auto-generated method stub}public void insert() throws Exception{Connection conn = null;Statement st = null;ResultSet rs = null;try{conn = JdbcUtils.getConnection();st = conn.createStatement();String sql = "insert into employee values(5,'貂蝉','352-7-5','2110-1-1','奉先之爱','6000.0','噬神之书')";int num = st.executeUpdate(sql);if(num>0){System.out.println("插入成功！");}}finally{JdbcUtils.release(conn, st, rs);}}public void update() throws Exception{Connection conn = null;Statement st = null;ResultSet rs = null;try{conn = JdbcUtils.getConnection();st = conn.createStatement();String sql = "update employee set ersume='纯阳剑' where id='3'";int num = st.executeUpdate(sql);if(num>0){System.out.println("更新成功！");}}finally{JdbcUtils.release(conn, st, rs);}}@Testpublic void getAll() throws Exception{Connection conn = null;Statement st = null;ResultSet rs = null;try{conn = JdbcUtils.getConnection();st = conn.createStatement();String sql = "select * from employee";rs= st.executeQuery(sql);List list = new ArrayList();while(rs.next()){Users user = new Users();user.setId(rs.getInt("id"));user.setUsername(rs.getString("username"));list.add(user);}System.out.println(list);}finally{JdbcUtils.release(conn, st, rs);}}}