这篇文章主要介绍了java 使用策略模式操作jdbc数据库的相关资料,这里提供实例实现对jdbc数据库的操作增删改查的功能，需要的朋友可以参考下
java 使用策略模式操作jdbc数据库
1：构造一个操作数据库的工具类，可以获得连接和释放连接
public class dbutil {
private static connection conn = null;
static { //静态初始块
try {
class.forname("com.mysql.jdbc.driver");
conn = drivermanager.getconnection("jdbc:mysql://127.0.0.1:3306/test", "root", "064319"); //初始化获取连接
} catch (classnotfoundexception e) {
e.printstacktrace();
} catch (sqlexception e) {
e.printstacktrace();
}
}
/**
* 释放连接
* @param rs
* @param psmt
* @param conn
* @throws sqlexception
*/
public static void closeall(resultset rs, preparedstatement psmt, connection conn) throws sqlexception {
if(rs != null) {
rs.close();
}
if(psmt != null) {
psmt.close();
}
if(conn != null) {
conn.close();
}
}
/**
* 获取连接
* @return
*/
public static connection getconnection() {
return conn;
}
/**
* 根据表的名字来获得表的列信息
* @param tablename
*/
public static void gettablecolumninfobytablename(string tablename) {
connection conn = getconnection();
resultset rs = null;
preparedstatement psmt = null;
string sql = "select * from " + tablename;
try {
psmt = conn.preparestatement(sql);
rs = psmt.executequery();
resultsetmetadata resultsetmetadata = rs.getmetadata();
for(int i = 1; i<= resultsetmetadata.getcolumncount(); i++) {
system.out.println(resultsetmetadata.getcolumnname(i));
}
} catch (sqlexception e) {
e.printstacktrace();
} finally {
try {
closeall(rs, psmt, conn);
} catch (sqlexception e) {
e.printstacktrace();
}
}
}
/**
* 根据表的名字来获得表的信息
* @param tablename
*/
public static void gettableinfobytablename(string tablename) {
connection conn = getconnection();
preparedstatement psmt = null;
resultset rs = null;
string sql = "select * from " + tablename;
try {
psmt = conn.preparestatement(sql);
rs = psmt.executequery();
while(rs.next()) {
resultsetmetadata resultsetmetadata = rs.getmetadata();
for(int i = 1; i<= resultsetmetadata.getcolumncount(); i++) {
if(i < resultsetmetadata.getcolumncount()) {
system.out.print(rs.getobject(resultsetmetadata.getcolumnname(i)) + ", ");
} else {
system.out.print(rs.getobject(resultsetmetadata.getcolumnname(i)));
}
}
system.out.println();
}
} catch (sqlexception e) {
e.printstacktrace();
} finally {
try {
closeall(rs, psmt, conn);
} catch (sqlexception e) {
e.printstacktrace();
}
}
}
}
2：构造一个操作数据库的basedao类
public class basedao {
/**
* 根据一些参数来保存相应的对象
* @param sql 要执行的sql语句
* @param params 为sql语句中相应的参数赋值
* @return
*/
protected boolean saveorupdate(string sql, object[] params) {
connection conn = null;
preparedstatement psmt = null;
boolean flag = false;
conn = dbutil.getconnection();
if(conn != null) {
try {
psmt = conn.preparestatement(sql);
for(int i = 1; i <= params.length; i++) {
psmt.setobject(i, params[i-1]);
}
if(psmt.executeupdate() > 0) {
flag = true;
}
} catch (sqlexception e) {
e.printstacktrace();
} finally {
try {
dbutil.closeall(null, psmt, conn);
} catch (sqlexception e) {
e.printstacktrace();
}
}
}
return flag;
}
/**
* 根据一定的参数获得某个具体的对象
* @param sql 要执行的sql语句
* @param params 为sql语句中相应的参数赋值
* @return
*/
public object queryforobject(string sql, object[] params, rowmapforobject rowmapforobject) {
connection conn = null;
preparedstatement psmt = null;
conn = dbutil.getconnection();
object obj = null;
resultset rs = null;
if(conn != null) {
try {
psmt = conn.preparestatement(sql);
if(params != null && params.length > 0) {
for(int i = 1; i <= params.length; i++) {
psmt.setobject(i, params[i - 1]);
}
}
rs = psmt.executequery();
obj = rowmapforobject.rowmapforobject(rs);
} catch (sqlexception e) {
e.printstacktrace();
} finally {
try {
dbutil.closeall(null, psmt, conn);
} catch (sqlexception e) {
e.printstacktrace();
}
}
}
return obj;
}
/**
* 根据相应的参数获得查询的结果集
* @param sql
* @param params
* @return
*/
public list queryforlist(string sql, object[] params, rowmapforlist rowmapforlist) {
connection conn = null;
preparedstatement psmt = null;
conn = dbutil.getconnection();
list list = null;
resultset rs = null;
if(conn != null) {
try {
psmt = conn.preparestatement(sql);
if(params != null && params.length > 0) {
for(int i = 1; i <= params.length; i++) {
psmt.setobject(i, params[i - 1]);
}
}
rs = psmt.executequery(sql);
list = new arraylist();
list = rowmapforlist.rowmapforlist(rs);
} catch (sqlexception e) {
e.printstacktrace();
} finally {
try {
dbutil.closeall(null, psmt, conn);
} catch (sqlexception e) {
e.printstacktrace();
}
}
}
return list;
}
}
3：新建一个studentdao类，该类继承自basedao，实现对student的管理
public class studentdao extends basedao {
/**
* 保存一个student的信息
*/
public boolean savestudent(student student) {
string sql = "insert into t_student(name, age) values(?, ?)";
object[] params = new object[]{student.getname(), student.getage()};
return super.saveorupdate(sql, params);
}
/**
* 根据id获得一个student的信息
* @param id
* @return
*/
public student getstudentbyid(long id) {
string sql = "select * from t_student where id=?";
object[] params = new object[]{id};
return (student)super.queryforobject(sql, params, new rowmapforobject() {
public object rowmapforobject(resultset rs) {
student student = null;
try {
if(rs != null && rs.next()) {
student = new student();
student.setage(rs.getint(student.age));
student.setid(rs.getlong(student.id));
student.setname(rs.getstring(student.name));
}
} catch (sqlexception e) {
e.printstacktrace();
}
return student;
}
});
}
/**
* 获得所有student的信息
* @return
*/
public list getstudentall() {
string sql = "select * from t_student";
list list = super.queryforlist(sql, null, new rowmapforlist() {
@override
public list rowmapforlist(resultset rs) {
list list = null;
try {
if(rs != null) {
list = new arraylist();
while(rs.next()) {
student student = new student();
student.setid(rs.getlong("id"));
student.setage(rs.getint("age"));
student.setname(rs.getstring("name"));
list.add(student);
}
}
} catch(sqlexception e) {
e.printstacktrace();
}
return list;
}
});
return list;
}
}
以上就是java如何利用策略模式操作jdbc数据库的实例分析的详细内容。