三个.java 文件DbUtils.java连接数据库的, Contact.java封装表contcat, ContactDao.java封装对表的操作,单独编译 DbUtils.java Contact.java能通过 .
ContactDao.java报错:
C:\Program Files\Apache Software Foundation\Tomcat 5.5\webapps\ww\WEB-INF\src>ja
vac ContactDao.java
ContactDao.java:18: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
public List<Contact> getAll() throws Exception {
^
ContactDao.java:52: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
public Contact get(Long id) throws Exception {
^
ContactDao.java:86: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
public void save(Contact contact) throws Exception {
^
ContactDao.java:110: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
public void update(Contact contact) throws Exception {
^
ContactDao.java:23: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
List<Contact> list = new ArrayList<Contact>();
^
ContactDao.java:23: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
List<Contact> list = new ArrayList<Contact>();
^
ContactDao.java:25: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
conn = DbUtils.getConn();
^
ContactDao.java:30: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
Contact contact = new Contact();
^
ContactDao.java:30: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
Contact contact = new Contact();
^
ContactDao.java:41: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
DbUtils.close(rs, state, conn);
^
ContactDao.java:57: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
Contact contact = null;
^
ContactDao.java:59: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
conn = DbUtils.getConn();
^
ContactDao.java:66: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
contact = new Contact();
^
ContactDao.java:76: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
DbUtils.close(rs, state, conn);
^
ContactDao.java:91: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
conn = DbUtils.getConn();一下是他们三个文件
package anni;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;public class DbUtils {
static {
try {
Class.forName("org.hsqldb.jdbcDriver");
} catch (ClassNotFoundException ex) {
System.err.println(ex);
}
} public static Connection getConn() {
try {
return DriverManager.getConnection("jdbc:hsqldb:res:/hsqldb/contact", "sa", "");
} catch (SQLException ex) {
System.err.println(ex);
return null;
}
}..............package anni;public class Contact {
private Long id;
private String username;
private String sex;
private String email;
private String qq;
private String descn; public Contact() {
} public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
} public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
} public String getSex() {
return sex;..............package anni;import java.util.ArrayList;
import java.util.List;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;public class ContactDao { /**
* 获得所有联系簿.
*
* @return contact列表
*/
public List<Contact> getAll() throws Exception {
Connection conn = null;
Statement state = null;
ResultSet rs = null; List<Contact> list = new ArrayList<Contact>();
try {
conn = DbUtils.getConn();
state = conn.createStatement();
rs = state.executeQuery("select * from contact");......
我搞了一天都没搞明白,希望能得到帮助! List<Contact> 是jdk1.5支持的泛型,我的Jdk是1.5,和这个有关吗?
ContactDao.java报错:
C:\Program Files\Apache Software Foundation\Tomcat 5.5\webapps\ww\WEB-INF\src>ja
vac ContactDao.java
ContactDao.java:18: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
public List<Contact> getAll() throws Exception {
^
ContactDao.java:52: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
public Contact get(Long id) throws Exception {
^
ContactDao.java:86: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
public void save(Contact contact) throws Exception {
^
ContactDao.java:110: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
public void update(Contact contact) throws Exception {
^
ContactDao.java:23: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
List<Contact> list = new ArrayList<Contact>();
^
ContactDao.java:23: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
List<Contact> list = new ArrayList<Contact>();
^
ContactDao.java:25: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
conn = DbUtils.getConn();
^
ContactDao.java:30: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
Contact contact = new Contact();
^
ContactDao.java:30: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
Contact contact = new Contact();
^
ContactDao.java:41: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
DbUtils.close(rs, state, conn);
^
ContactDao.java:57: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
Contact contact = null;
^
ContactDao.java:59: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
conn = DbUtils.getConn();
^
ContactDao.java:66: cannot find symbol
symbol : class Contact
location: class anni.ContactDao
contact = new Contact();
^
ContactDao.java:76: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
DbUtils.close(rs, state, conn);
^
ContactDao.java:91: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
conn = DbUtils.getConn();一下是他们三个文件
package anni;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;public class DbUtils {
static {
try {
Class.forName("org.hsqldb.jdbcDriver");
} catch (ClassNotFoundException ex) {
System.err.println(ex);
}
} public static Connection getConn() {
try {
return DriverManager.getConnection("jdbc:hsqldb:res:/hsqldb/contact", "sa", "");
} catch (SQLException ex) {
System.err.println(ex);
return null;
}
}..............package anni;public class Contact {
private Long id;
private String username;
private String sex;
private String email;
private String qq;
private String descn; public Contact() {
} public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
} public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
} public String getSex() {
return sex;..............package anni;import java.util.ArrayList;
import java.util.List;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;public class ContactDao { /**
* 获得所有联系簿.
*
* @return contact列表
*/
public List<Contact> getAll() throws Exception {
Connection conn = null;
Statement state = null;
ResultSet rs = null; List<Contact> list = new ArrayList<Contact>();
try {
conn = DbUtils.getConn();
state = conn.createStatement();
rs = state.executeQuery("select * from contact");......
我搞了一天都没搞明白,希望能得到帮助! List<Contact> 是jdk1.5支持的泛型,我的Jdk是1.5,和这个有关吗?
你编译工程类的时候编译level太低了,设置的高一些
右键点工程->选属性->java Compiler->选中enable project specific setting ->
->compiler compliance level ->选5.0,保存退出,重新编译工程并部署
s\anni>javac *.java
ContactDao.java:25: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
conn = DbUtils.getConn();
^
ContactDao.java:41: cannot find symbol
symbol : variable DbUtils
location: class anni.ContactDao
DbUtils.close(rs, state, conn);
^
java 文件不要放到 WEB-INF 下面去。
你编译工程类的时候编译level太低了,设置的高一些
右键点工程->选属性->java Compiler->选中enable project specific setting ->
->compiler compliance level ->选5.0,保存退出,重新编译工程并部署
WEB-INF/classes/anni/*.class
你最好用IDE部署一下。
我把你的三个文件弄过来能通过编译
我的是这样的:
文件E:\anni下
E:\anni javac *.java
能通过编译