jdbc接続データベースの3つの文
3種類のjdbc接続はそれぞれ:通常のjdbc,PreparedStatement,CallableStatement
注意:space.tools.print.Printクラスは、印刷出力をカスタマイズするツールクラスです.
package jdbc;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import org.apache.log4j.Logger;
import static space.tools.print.Print.printfgf;
public class Test {
private Connection conn = null;
private ResultSet rs = null;
protected Logger log = Logger.getLogger(this.getClass());
public Test() {
initConn("jdbc:mysql://localhost:3306/zhaopin", "root", "your_pswd");
}
public Test(String url, String username, String pswd) {
initConn(url, username, pswd);
}
public static void main(String[] args) {
Test test = new Test();
test.jdbc();
printfgf();
test.jdbcPS();
printfgf();
test.jdbcCS();
}
/**
* jdbc
*/
public void jdbc() {
try {
Statement stmt = conn.createStatement();
String sql = "select * from article limit 1 ;";
rs = stmt.executeQuery(sql);
while (rs.next()) {
System.out.println(rs.getString(1) + "," + rs.getString(2) + "," + rs.getString(3) + ","
+ rs.getString(4));
}
} catch (SQLException e) {
e.printStackTrace();
}
}
/**
* PreparedStatement
*/
public void jdbcPS() {
try {
String sql = "select * from article limit ? ";
PreparedStatement ps = conn.prepareStatement(sql); // preparedstatement sql
ps.setInt(1, 2); // ?
rs = ps.executeQuery(); // preparedstatement , ;
while (rs.next()) {
System.out.println(rs.getString(1) + "," + rs.getString(2) + "," + rs.getString(3) + ","
+ rs.getString(4));
}
} catch (SQLException e) {
e.printStackTrace();
}
}
/**
* CallableStatement ,
*/
public void jdbcCS() {
// : CREATE PROCEDURE listArticle () SELECT * FROM article LIMIT 3
try {
CallableStatement cs = conn.prepareCall("{call listArticle()}");
rs = cs.executeQuery();
while (rs.next()) {
System.out.println(rs.getString(1) + "," + rs.getString(2) + "," + rs.getString(3) + ","
+ rs.getString(4));
}
} catch (SQLException e) {
e.printStackTrace();
}
}
private void initConn(String url, String username, String pswd) {
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(url, username, pswd);
System.out.println(" ");
} catch (SQLException ex) {
System.out.println(ex.getMessage() + " ");
} catch (ClassNotFoundException ex) {
System.out.println(ex.getMessage() + " ");
}
}
}
注意:space.tools.print.Printクラスは、印刷出力をカスタマイズするツールクラスです.
package space.tools.print;
/**
* This class comes from System.out.println() and System.out.print()
* Helps to use less words to print something.
* Before using the static methods in this class,use "import space.tools.print;" to import this class
* After import this class,you can use the static methods without "Print." before,just white the method'name is ok.
*/
public class Print
{
/**
* print something,then goto a new line.
*/
public static void print(Object o)
{
System.out.println(o);
}
/**
* print nothing,just goto a new line.
*/
public static void print()
{
System.out.println();
}
/**
* just print something in present line.
*/
public static void printnb(Object o)
{
System.out.print(o);
}
/**
* print fgf.
*/
public static void printfgf()
{
System.out.println("
-----------------------");
}
public static void printfgf(int n)
{
char c='-';
StringBuilder sb=new StringBuilder();
for(int i=0;i<n;i++)
sb.append(c);
System.out.println(sb);
}
public static void printfgf(char c,int n)
{
StringBuilder sb=new StringBuilder();
for(int i=0;i<n;i++)
sb.append(c);
System.out.println(sb);
}
public static void printArray(Object[] os)
{
StringBuilder sb=new StringBuilder("["+(os.length==0?"":"
"));
for(Object o:os)
sb.append(o+"
");
sb.append("]");
System.out.println(sb);
}
}