jdbc连接数据库的3种语句
3种jdbc连接分别是：普通的jdbc，PreparedStatement，CallableStatementpackage 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(); } /*** 普通的jdbc语句*/ 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();} } /*** 使用 PreparedStatement 语句*/ public void jdbcPS() {try { String sql = "select * from article limit ? "; PreparedStatement ps = conn.prepareStatement(sql); // 以 preparedstatement sql 语句 字符串作为参数 ps.setInt(1, 2); // 填充 ? 参数 rs = ps.executeQuery(); // 执行 preparedstatement 语句，获得结果； while (rs.next()) { System.out.println(rs.getString(1) + "," + rs.getString(2) + "," + rs.getString(3) + "," + rs.getString(4)); }} catch (SQLException e) { e.printStackTrace();} } /*** 使用 CallableStatement 语句，调用数据库中的存储过程*/ public void jdbcCS() {// 存储过程： CREATE PROCEDURE listArticle () SELECT * FROM article LIMIT 3try { 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("连接成功");} catch (SQLException ex) { System.out.println(ex.getMessage() + "数据库配置错误");} catch (ClassNotFoundException ex) { System.out.println(ex.getMessage() + "驱动加载错误");} }} 注：space.tools.print.Print 类，是自定义的一个打印输出的工具类，
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("\n-----------------------");}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?"":"\n"));for(Object o:os)sb.append(o+"\n");sb.append("]");System.out.println(sb);}}
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