既然谈到面向对象，所以，先把连接信息给搞个对象出来：
public class DBInfo {
private String driver;
private String host;
private String port;
private String user;
private String pwd;
private String dataBase;
public DBInfo(){
this.driver = "com.mysql.jdbc.Driver";
this.host = "";
this.port = "";
this.user = "";
this.pwd = "";
this.dataBase = "";
}
public String getDriver() {
return driver;
}
public void setDriver(String driver) {
this.driver = driver;
}
public String getHost() {
return host;
}
public void setHost(String host) {
this.host = host;
}
public String getDataBase() {
return dataBase;
}
public void setDataBase(String dataBase) {
this.dataBase = dataBase;
}
public String getPort() {
return port;
}
public void setPort(String port) {
this.port = port;
}
public String getUser() {
return user;
}
public void setUser(String user) {
this.user = user;
}
public String getPwd() {
return pwd;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
}
既然是操作数据库，我们就把数据库的字段给对象化一下，也就是持久化：在定义变量时，我们搞个约定，比如，数据库字段名为:test_login_name,则定义变量时为：testLoginName.
public class UserInfo {
private int id;
private String testName;
private String testAge;
private String testHeight;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getTestName() {
return testName;
}
public void setTestName(String testName) {
this.testName = testName;
}
public String getTestAge() {
return testAge;
}
public void setTestAge(String testAge) {
this.testAge = testAge;
}
public String getTestHeight() {
return testHeight;
}
public void setTestHeight(String testHeight) {
this.testHeight = testHeight;
}
}
好，现在有了javabean,有了数据库连接的对象了，再加一个枚举来保存数据库与bean之间的映射关系：
public enum TableBean {
USER_INFO("com.test.bean.UserInfo");
private String value;
private TableBean(String value){
this.value = value;
}
public String getValue(){
return value;
}
@Override
public String toString() {
return value;
}
public static void main(String[] args){
System.out.println(TableBean.USER_INFO);
}
}
再加一个保存ResultSetMetaData信息的类:
public class MetaData {
public static Map<String, ResultSetMetaData> metaData = new HashMap<String, ResultSetMetaData>();
}
余下就是操作数据库了：
public class ConnectToMySQL {
private DBInfo dbInfo;
private Connection conn = null;
private Statement stmt = null;
public ConnectToMySQL(){
dbInfo = new DBInfo();
}
public DBInfo getDbInfo() {
return dbInfo;
}
public void setDbInfo(DBInfo dbInfo) {
this.dbInfo = dbInfo;
}
public void connect() {
this.close();
this.connectMySQL();
}
public synchronized void close() {
try {
if (stmt != null) {
stmt.close();
stmt = null;
}
if (conn != null) {
conn.close();
conn = null;
}
} catch (SQLException e) {
e.printStackTrace();
}
}
private synchronized void connectMySQL() {
try {
Class.forName(dbInfo.getDriver()).newInstance();
conn = (Connection) DriverManager.getConnection("jdbc:mysql://"
+ dbInfo.getHost() + "/" + dbInfo.getDataBase() +"?useUnicode=true&characterEncoding=utf-8", dbInfo.getUser(),dbInfo.getPwd());
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}
private void statement() {
if (conn == null) {
this.connectMySQL();
}
try {
stmt = (Statement) conn.createStatement();
} catch (SQLException e) {
e.printStackTrace();
}
}
private ResultSet resultSet(String sql) {
ResultSet rs = null;
if (stmt == null) {
this.statement();
}
try {
rs = stmt.executeQuery(sql);
} catch (SQLException e) {
e.printStackTrace();
}
return rs;
}
private void executeUpdate(String sql){
if (stmt == null) {
this.statement();
}
try {
stmt.executeUpdate(sql);
} catch (SQLException e) {
System.out.println(sql);
e.printStackTrace();
}
}
public List<Object> query(String tableInfo, String sql) {
List<Object> list = new ArrayList<Object>();
ResultSet rs = this.resultSet(sql);
try {
ResultSetMetaData md = rs.getMetaData();
int cc = md.getColumnCount();
while (rs.next()) {
Object object = this.getBeanInfo(tableInfo);
for (int i = 1; i <= cc; i++) {
String cn = md.getColumnName(i);
this.reflectSetInfo(object, this.changeColumnToBean(cn,"set"), rs.getObject(cn));
}
list.add(object);
}
} catch (SQLException e) {
e.printStackTrace();
}
return list;
}
public void insert(String table, Object object){
String sql = "";
try {
this.getMetaData(table);
ResultSetMetaData md = MetaData.metaData.get(table);
int cc = md.getColumnCount();
String insertColumn = "";
String insertValue = "";
for (int i = 2; i <= cc; i++) {
String cn = md.getColumnName(i);
Object gValue = this.reflectGetInfo(object, this.changeColumnToBean(cn,"get"));
if(gValue.getClass().getSimpleName().equals("String")){
gValue = "\""+gValue+"\"";
}
if("".equals(insertColumn)){
insertColumn += cn;
insertValue += gValue;
}else{
insertColumn += ","+cn;
insertValue += ","+gValue;
}
}
sql = "insert into "+table+" ("+insertColumn+") values ("+insertValue+")";
this.executeUpdate(sql);
} catch (SQLException e) {
e.printStackTrace();
}
}
private void getMetaData(String table){
if(!MetaData.metaData.containsKey(table)){
ResultSet rs = this.resultSet("select * from "+table+" limit 0,1");
try {
MetaData.metaData.put(table, rs.getMetaData());
} catch (SQLException e) {
e.printStackTrace();
}
}
}
private Object getBeanInfo(String tableInfo){
Object object = null;
try {
object = Class.forName(tableInfo).newInstance();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return object;
}
private void reflectSetInfo(Object object, String methodName, Object parameter){
try {
Class<? extends Object> ptype = parameter.getClass();
if(parameter.getClass().getSimpleName().equals("Integer")){
ptype = int.class;
}
Method method = object.getClass().getMethod(methodName, ptype);
method.invoke(object, parameter);
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
private Object reflectGetInfo(Object object, String methodName){
Object value = null;
try {
Method method = object.getClass().getMethod(methodName);
Object returnValue = method.invoke(object);
if(returnValue!=null){
value = returnValue.toString();
}else{
value = "";
}
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
return value;
}
private String columnToBean(String column){
if(column.contains("_")){
int index = column.indexOf("_");
String beanName = column.substring(0, index)
+column.substring(index+1, index+2).toUpperCase()
+column.substring(index+2, column.length());
return beanName;
}
return column;
}
private String changeColumnToBean(String column, String ext){
String[] col = column.split("_");
for (int i = 0; i < col.length; i++) {
column = this.columnToBean(column);
}
column =column.replaceFirst(column.substring(0, 1), column.substring(0, 1).toUpperCase());
column = ext+column;
return column;
}
public static void main(String[] args) throws SQLException {
ConnectToMySQL c = new ConnectToMySQL();
c.connect();
List<Object> list = c.query(TableBean.APK_INFO.toString(), "select * from user_info");
c.insert("user_info", (UserInfo)list.get(0));
c.close();
}
}
仔细看看吧，query出来就是对象的集合，insert时，就是表名与对象就行了，至于update与delete，大家自已扩展吧！
如果把这个摸清楚，spring操作mysql数据库的原理，你也就差不多了！