本文實(shí)例講述了java使用preparedstatement接口及resultset結(jié)果集的方法。分享給大家供大家參考，具體如下：
說明：
1.preparedstatement接口繼承statement,它的實(shí)例包含已編譯的sql語句，執(zhí)行速度要快于statement。
2.preparedstatement繼承了statement的所有功能，三種方法executeupdate、executequery、execute不再需要參數(shù)。
3.在jdbc應(yīng)用中，一般都用preparedstatement，而不是statement。
便于操作，先做一些封裝：
對(duì)連接數(shù)據(jù)庫，關(guān)閉連接封裝，在之前博客中已經(jīng)提到dbutil.java;
對(duì)數(shù)據(jù)庫表進(jìn)行封裝，這里是對(duì)我的數(shù)據(jù)庫中comp表進(jìn)行操作，因此封裝如下：
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package com.mysqltest.jdbc.modelcomp;public class compmember { private int id; private string name; private int age; private double salary; /** * 構(gòu)造函數(shù)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; } /** * 重載構(gòu)造函數(shù) * @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 /** * 改寫tostring,使得顯示更好 */ public string tostring() { return "["+this.id+"]"+this.name+","+this.age+","+this.salary; }} |
然后利用preparedstatement接口實(shí)現(xiàn)增的操作：
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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添加成員 * @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();//中間不用傳入sql dbutil.close(pstmt, con); //preparedstatement是子類，用父類關(guān)閉也行 return result; } public static void main(string[] args) throws exception { compmember mem = new compmember("劉翔", 24, 8000.00); int result = addmember(mem); if (result==1) { system.out.println("添加成功"); } else { system.out.println("添加失敗"); } }} |
再利用preparedstatement接口實(shí)現(xiàn)查詢，并運(yùn)用resultset結(jié)果集：
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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(); /** * 遍歷查詢結(jié)果 * @throws exception */ @suppresswarnings("unused") private static void listmem1() throws exception { connection con = dbutil.getcon();// 獲取連接 string sql = "select * from comp"; preparedstatement pstmt = con.preparestatement(sql); resultset rs = pstmt.executequery();// 返回結(jié)果集 // next()將光標(biāo)向后一行 while (rs.next()) { int id = rs.getint(1);// 獲取第一列的值id string name = rs.getstring(2);// int age = rs.getint(3); double salary = rs.getdouble(4); system.out.println("編號(hào)：" + id + "姓名：" + name + "年齡：" + age + "工資：" + salary); system.out.println("+====================================+"); } } /** * 遍歷查詢結(jié)果方法2 * @throws exception */ @suppresswarnings("unused") private static void listmem2() throws exception { connection con = dbutil.getcon();// 獲取連接 string sql = "select * from comp"; preparedstatement pstmt = con.preparestatement(sql); resultset rs = pstmt.executequery();// 返回結(jié)果集 // next()將光標(biāo)向后一行 while (rs.next()) { int id = rs.getint("id");// 獲取第一列的值id string name = rs.getstring("name");// int age = rs.getint("age"); double salary = rs.getdouble("salary"); system.out.println("編號(hào)：" + id + "姓名：" + name + "年齡：" + age + "工資：" + salary); system.out.println("+====================================+"); } } private static list<compmember> listmem3() throws exception{ list<compmember> memlist = new arraylist<compmember>(); connection con = dbutil.getcon();// 獲取連接 string sql = "select * from comp"; preparedstatement pstmt = con.preparestatement(sql); resultset rs = pstmt.executequery();// 返回結(jié)果集 // next()將光標(biāo)向后一行 while (rs.next()) { int id = rs.getint("id");// 獲取第一列的值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<compmember> memlist = listmem3(); for (compmember mem : memlist) { //遍歷集合的每個(gè)元素 system.out.println(mem); } }} |
希望本文所述對(duì)大家java程序設(shè)計(jì)有所幫助。
原文鏈接：https://blog.csdn.net/u010986080/article/details/51813056
