多平台统一管理软件接口,如何实现多平台统一管理软件接口
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2023-01-26
Java使用PreparedStatement接口及ResultSet结果集的方法示例
本文实例讲述了java使用PreparedStatement接口及ResultSet结果集的方法。分享给大家供大家参考,具体如下:
说明:
1.PreparedStatement接口继承Sthttp://atement,它的实例包含已编译的SQL语句,执行速度要快于Statement。
2.PreparedStatement继承了Statement的所有功能,三种方法executeUpdate、executeQuery、execute不再需要参数。
3.在JDBC应用中,一般都用PreparedStatement,而不是Statement。
便于操作,先做一些封装:
对连接数据库,关闭连接封装,在之前博客中已经提到DbUtil.java;
对数据库表进行封装,这里是对我的数据库中comp表进行操作,因此封装如下:
package com.mysqltest.jdbc.modelComp;
public class CompMember {
private int id;
private String name;
private int age;
private double salary;
/**
* 构造函数1
* @param name
* @param age
* @param salary
*/
public CompMember(String name, int age, double salary) {
super();
this.name = name;
this.age = age;
this.salary = salary;
}
/**
* 重载构造函数
* @param id
* @param name
* @param age
* @param salary
*/
public CompMember(int id, String name, int age, double salary) {
super();
this.id = id;
this.name = name;
this.age = age;
this.salary = salary;
}
/**
* get,set方法
*/
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
@Override
/**
* 改写toString,使得显示更好
*/
public String toString() {
return "["+this.id+"]"+this.name+","+this.age+","+this.salary;
}
}
然后利用PreparedStatement接口实现增的操作:
package com.mysqltest.jdbc.xiao1;
import java.sql.Connection;
import java.sql.PreparedStatement;
import com.mysqltest.jdbc.modelComp.CompMember;
import com.mysqltest.jdbc.util.DbUtil;
public class PstatementTest {
private static DbUtil dbUtil = new DbUtil();
/**
* 用PreparedStatement添加成员
* @param mem
* @return
* @throws Exception
*/
private static int addMember(CompMember mem) throws Exception{
Connection con = dbUtil.getCon();
String sql = "insert into comp values(null,?,?,?)";
PreparedStatement pstmt = con.prepareStatement(sql);
pstmt.setString(1, mem.getName());
pstmt.setInt(2, mem.getAge());
pstmt.setDouble(3, mem.getSalary());
int result = pstmt.executeUpdate();//中间不用传入sql
dbUtil.close(pstmt, con); //preparedStatement是子类,用父类关闭也行
return result;
}
public static void main(String[] args) throws Exception {
CompMember mem = new CompMember("刘翔", 24, 8000.00);
int result = addMember(mem);
if (result==1) {
System.out.println("添加成功");
} else {
System.out.println("添加失败");
}
}
}
再利用PreparedStatement接口实现查询,并运用ResultSet结果集:
package com.mysqltest.jdbc.xiao2;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import com.mysqltest.jdbc.modelComp.CompMember;
import com.mysqltest.jdbc.util.DbUtil;
public class ResultsetTest {
private static DbUtil dbUtil = new DbUtil();
/**
* 遍历查询结果
* @throws Exception
*/
@SuppressWarnings("unused")
private static void listMem1() throws Exception {
Connection con = dbUtil.getCon();// 获取连接
String sql = "select * from comp";
PreparedStatement pstmt = con.prepareStatement(sql);
ResultSet rs = pstmt.executeQuery();// 返回结果集
// next()将光标向后一行
while (rs.next()) {
int id = rs.getInt(1);// 获取第一列的值id
String name = rs.getString(2);//
int age = rs.getInt(3);
double salary = rs.getDouble(4);
System.out.println("编号:" + id + "姓名:" + name + "年龄:" + age + "工资:" + salary);
System.out.println("+====================================+");
}
}
/**
* 遍历查询结果方法2
* @throws Exception
*/
@SuppressWarnings("unused")
private static void listMem2() throws Exception {
Connection con = dbUtil.getCon();// 获取连接
String sql = "select * from comp";
PreparedStatement pstmt = con.prepareStatement(sql);
ResultSet rs = pstmt.executeQuery();// 返回结果集
// next()将光标向后一行
while (rs.next()) {
int id = rs.getInt("id");// 获取第一列的值id
String name = rs.getString("name");//
int age = rs.getInt("age");
double salary = rs.getDouble("salary");
System.out.println("编号:" + id + "姓名:" + name + "年龄:" + age + "工资:" + salary);
System.out.println("+====================================+");
}
}
private static List
List
Connection con = dbUtil.getCon();// 获取连接
String sql = "select * from comp";
PreparedStatement pstmt = con.prepareStatement(sql);
ResultSet rs = pstmt.executeQuery();// 返回结果http://集
// next()将光标向后一行
while (rs.next()) {
int id = rs.getInt("id");// 获取第一列的值id
String name = rs.getString("name");//
int age = rs.getInt("age");
double salary = rs.getDouble("salary");
CompMember mem = new CompMember(id, name, age, salary);
memList.add(mem);//添加到List中
}
return memList;
}
public static void main(String[] args) throws Exception {
// listMem1();
// listMem2();
List
for (CompMember mem : memList) { //遍http://历集合的每个元素
System.out.println(mem);
}
}
}
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