jdbc2
结果可以回滚结果集可以更新，影响数据库的更新
批处理
Statement stm=conn.createStatement();
stm2=conn.createStatement(int value1,int value2);
value1:是否可滚动
ResultSet.TYPE_SCROLL_INSENCITIVE
value2:是否可更新
ResultSet.CONCUR_UPDABLE
rs=stm2.executeQuery();
pstm=conn.prepareStatement(sql,int,int);
数据库表数据的分页
1.db--sql
子查询和Rownum
2.jdbc---->可滚动的结果集
String sql="select * from s_emp order by start_date";
rs=stm.execute(sql);
int num=1;
rs.absolute(5);
while(rs.next()){
if(num>5) return;
.........
}
int[] a=stm.executeBatch();
stm批处理里缓存的是sql命令
pstm批处理里缓存的是数据
Object----->db
class(entity)-------table
object(persist object)--------row
field------column(oid-----pk)
relation---------> pk fk
class Student{
private Integer oid;
String name;
int age;
String sex;
public Student(String name,int age,String sex){
}
}
Student s1=new Student("zhangsan",18,"male");
Student s2=new Student("lisi",19,"male");
Student s3=new Student("zhangsan",20,"male");
----------------------------------------------------
one-to-one( Car ---- License )
1.java
class Car{
//oid
private Integer cid;
// 业务属性
private String manufactory;
private String productType;
//关系属性
private License license;
// get 和 set
// 有参和无参的构造方法
public void addLicense(License license){
this.license=license;
license.addCar(this);
}
public void removeLicense(){
this.license.removeCar();
this.license=null;
}
}
class License{
private Integer lid;
private String serialNum;
private String LicenseType;
private Car car;
// get 和 set
// 有参和无参的构造方法
public void addCar(Car car){
this.car=car;
}
public void removeCar(){
this.car=null;
}
}
2. db
create table jdbc_car
( cid number(7) primary key,
manufactory varchar2(15) not null,
producttype varchar2(15) not null,
);
create table jdbc_license
( lid number(7) primary key,
serialnum varchar2(15) not null,
licensetype varchar2(15) not null,
car_id number(7) references jdbc_car(cid) unique
);
3. dao( CarDao--->jdbc_car , LicenseDao--->jdbc_license)
class CarDao{
public void insertCar(Car c) throws Exception{
1.insert into cartable
2.c.setCid(?);
3.insert into license
4.l.setLid(?);
}
public void deleteCar1(Car c) throws Exception{
1.delete from license
2.delete from car
3.c.setOid(null);
4.license.setLid(null);
5.c.removeLicense(l);
}
public void deleteCar(Car c) throws Exception{
1.update license set car_id=null
2.delete from car
3.c.setOid(null);
4.license.setLid(null);
5.c.removeLicense(l);
}
public void updateCar(Car c) throws Exception{
1. update car table;
2. update license table set car_id=null;
3?
}
public Car queryByCid(Integer cid) throws Exception{
db-->1.select car table
2.select license table
内存--> 3. car.addLicense(license);
4.return car;
}
}
main(){
Car c=queryByCarid(222);
c.addLicense(license);
dao.update(c);
}
1. 维护数据库
2. 维护内存中的oid
3. 维护关系
TestBatch.Java
import java.sql.*;
public class TestBatch {
public static void main(String[] args) {
Connection conn=null;
Statement stm=null;
try{
conn=JdbcUtil.getConnection();
conn.setAutoCommit(false);
stm=conn.createStatement();
String sql="insert
into jdbc_account(id,name,passwd,cardid,balance,personId)" +" values(jdbc_account_seq.nextval,'liucy','000','000',10,'0000')";
stm.addBatch(sql);
sql="update jdbc_account set balance=100000 where name='luxw'";
stm.addBatch(sql);
sql="delete from jdbc_account where id=110 or id=104";
stm.addBatch(sql);
int[] a=stm.executeBatch();
for(int i:a){
System.out.println(i);
}
conn.commit();
}catch(Exception e){
e.printStackTrace();
if(conn!=null) try{ conn.rollback();
} catch(Exception ee){}
}finally{
JdbcUtil.release(null, stm, conn);
}
}
}
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
public class TestBlob {
public static void insertBlob(String filename){
Connection conn=null;
Statement stm=null;
ResultSet rs=null;
try{
conn=JdbcUtil.getConnection();
conn.setAutoCommit(false);
stm=conn.createStatement();
/*
* empty_blob()是Oracle提供的单行函数,作用向表里的
* blob列插入一个空的blob字段,blob字段的值随后用IO
* 流向数据库里写入
*/
String sql="insert into largetable(id,name,largefile)"
+" values(3,'file3',empty_blob())";
stm.executeUpdate(sql);
sql="select largefile from largetable where id=3";
rs=stm.executeQuery(sql);
if(rs.next()){
Blob blo=rs.getBlob(1);
System.out.println(blo.getClass().getName());
oracle.sql.BLOB bo=(oracle.sql.BLOB)blo;
OutputStream os=bo.getBinaryOutputStream();
InputStream is=new FileInputStream(filename);
byte[] b=new byte;
int len=0,num=0;
while(true){
len=is.read(b);
if(len<=0) break;
os.write(b,0,len);
if(++num%10==0){
System.out.println("10 k ok");
}
}
is.close();
os.close();
}
conn.commit();
}catch(Exception e){
if(conn!=null) try{ conn.rollback();} catch(Exception ee){}
}finally{
JdbcUtil.release(null,stm,conn);
}
}
public static void queryBlob(String name){
Connection conn=null;
Statement stm=null;
ResultSet rs=null;
try{
conn=JdbcUtil.getConnection();
conn.setAutoCommit(false);
stm=conn.createStatement();
String sql="select largefile from largetable where name='"+name+"'";
System.out.println(sql);
rs=stm.executeQuery(sql);
if(rs.next()){
Blob blo=rs.getBlob(1);
System.out.println(blo);
InputStream is=blo.getBinaryStream();
OutputStream os=new FileOutputStream("copy.rar");
byte[] b=new byte;
int len=0,num=0;
while(true){
len=is.read(b);
if(len<=0) break;
os.write(b,0,len);
if(++num%100==0){
System.out.println("1m ok");
}
}
is.close();
os.close();
}
conn.commit();
}catch(Exception e){
if(conn!=null) try{ conn.rollback();} catch(Exception ee){}
}finally{
JdbcUtil.release(null,stm,conn);
}
}
public static void main(String[] args) {
queryBlob("file3");
}
}
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