三个实体类
Location.java
publicclassLocation{
privateIntegerlocation_id;
privateStringcity;
//...
}
Department.java
publicclassDepartment{
privateIntegerdepartment_id;
privateStringdepartmentName;
privateIntegerlocation_id;
//...
}
Employee.java
publicclassEmployee{
privateIntegeremployeeId;
privateStringlastName;
privateStringemail;
privatedoublesalary;
privateIntegerdepartment_id;
//...
}
WebContent下的emplooyes.jsp中只有一行代码，跳转到servlet
<%
response.sendRedirect("EmployeeServlet?method=listLocations");
%>
EmployeeServlet.java
publicclassEmployeeServletextendsHttpServlet{
privatestaticfinallongserialVersionUID=1L;
protectedvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)throwsServletException,IOException{
StringmethodName=request.getParameter("method");
try{
Methodmethod=getClass().getDeclaredMethod(methodName,HttpServletRequest.class,HttpServletResponse.class);
method.invoke(this,request,response);
}catch(Exceptione){
e.printStackTrace();
}
}
protectedvoidlistLocations(HttpServletRequestrequest,IOException{
Connectionconnection=DBManager.getConnection();
Stringsql="select*fromlocation";
List<Location>locations=newArrayList<Location>();
Statementstatement=null;
ResultSetresultSet=null;
Locationlocation=null;
try{
statement=connection.createStatement();
resultSet=statement.executeQuery(sql);
while(resultSet.next()){
location=newLocation();
location.setCity(resultSet.getString("city"));
location.setLocation_id(resultSet.getInt("location_id"));
locations.add(location);
}
}catch(sqlExceptione){
e.printStackTrace();
}finally{
DBManager.close(resultSet,statement,connection);
}
request.setAttribute("locations",locations);
request.getRequestDispatcher("/WEB-INF/pages/employees.jsp").forward(request,response);
}
protectedvoidlistDepartments(HttpServletRequestrequest,IOException{
intlocationId=Integer.parseInt(request.getParameter("locationId"));
Stringsql="select*fromdepartmentwherelocation_id="+locationId;
Connectionconnection=DBManager.getConnection();
List<Department>departments=newArrayList<Department>();
Departmentdepartment=null;
ResultSetresultSet=null;
Statementstatement=null;
try{
statement=connection.createStatement();
resultSet=statement.executeQuery(sql);
while(resultSet.next()){
department=newDepartment();
department.setDepartmentName(resultSet.getString("departmentName"));
department.setDepartment_id(resultSet.getInt("department_id"));
department.setLocation_id(resultSet.getInt("location_id"));
departments.add(department);
}
}catch(sqlExceptione){
e.printStackTrace();
}finally{
DBManager.close(resultSet,connection);
}
ObjectMappermapper=newObjectMapper();
Stringresult=mapper.writeValueAsString(departments);
System.out.println(result);
response.setContentType("text/javascript");
response.setCharacterEncoding("UTF-8");
response.getWriter().print(result);
}
protectedvoidlistEmployees(HttpServletRequestrequest,IOException{
intdepartment_id=Integer.parseInt(request.getParameter("department_id"));
Stringsql="select*fromemployeewheredepartment_id="+department_id;
Connectionconnection=DBManager.getConnection();
Statementstatement=null;
ResultSetresultSet=null;
List<Employee>employees=newArrayList<Employee>();
Employeeemployee=null;
try{
statement=connection.createStatement();
resultSet=statement.executeQuery(sql);
while(resultSet.next()){
employee=newEmployee();
employee.setDepartment_id(resultSet.getInt("department_id"));
employee.setEmail(resultSet.getString("email"));
employee.setEmployeeId(resultSet.getInt("employee_id"));
employee.setLastName(resultSet.getString("last_name"));
employee.setSalary(resultSet.getDouble("salary"));
employees.add(employee);
}
}catch(sqlExceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}finally{
DBManager.close(resultSet,connection);
}
ObjectMappermapper=newObjectMapper();
Stringresult=mapper.writeValueAsString(employees);
System.out.println(result);
response.setContentType("text/javascript");
response.setCharacterEncoding("UTF-8");
response.getWriter().print(result);
}
protectedvoidlistEmployeeInfo(HttpServletRequestrequest,IOException{
intemployeeId=Integer.parseInt(request.getParameter("employeeId"));
Stringsql="select*fromemployeewhereemployee_id="+employeeId;
System.err.println(sql);
Connectionconnection=DBManager.getConnection();
Statementstatement=null;
ResultSetresultSet=null;
Employeeemployee=null;
try{
statement=connection.createStatement();
resultSet=statement.executeQuery(sql);
if(resultSet.next()){
employee=newEmployee();
employee.setDepartment_id(resultSet.getInt("department_id"));
employee.setEmail(resultSet.getString("email"));
employee.setEmployeeId(resultSet.getInt("employee_id"));
employee.setLastName(resultSet.getString("last_name"));
employee.setSalary(resultSet.getDouble("salary"));
}
}catch(Exceptione){
e.printStackTrace();
}finally{
DBManager.close(resultSet,connection);
}
ObjectMappermapper=newObjectMapper();
Stringresult=mapper.writeValueAsString(employee);
System.out.println(result);
response.setContentType("text/javascript");
response.setCharacterEncoding("UTF-8");
response.getWriter().print(result);
}
publicstaticvoidmain(String[]args){
System.out.println(DBManager.getConnection());
}
}
/WEB-INF/pages/employees.jsp浏览器不可达，只能通过servlet跳转到该页面
<%@pagelanguage="java"contentType="text/html;charset=UTF-8" pageEncoding="UTF-8"%> <%@taglibprefix="c"uri="http://java.sun.com/jsp/jstl/core"%> <!DOCTYPEhtmlPUBLIC"-//W3C//DTDHTML4.01Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <Metahttp-equiv="Content-Type"content="text/html;charset=UTF-8"> <title>Inserttitlehere</title> <scripttype="text/javascript" src="${pageContext.request.contextPath}/js/jquery-1.11.1.min.js"></script> <scripttype="text/javascript" src="${pageContext.request.contextPath}/js/jquery.blockUI.js"></script> <scripttype="text/javascript"> $(function(){ $(document).ajaxStart(function(){ //使用blockUI。ajax请求发出时执行 $.blockUI({ message:$('#loading'),css:{ top:($(window).height()-400)/2+'px',left:($(window).width()-400)/2+'px',width:'400px' },overlayCSS:{backgroundColor:'#00f'} }) }).ajaxStop($.unblockUI); $("#city").change(function(){ $("#departmentoption:not(:first)").remove(); varlocation_id=$(this).val(); if(location_id!=""){ varurl="EmployeeServlet?method=listDepartments"; varargs={"locationId":location_id,"time":newDate()}; $.getJSON(url,args,function(data){ if(data.length==0){ alert("当前城市没有部门"); }else{ for(vari=0;i<data.length;i++){ vardeptName=data[i].departmentName; vardeptId=data[i].department_id; //alert(deptName); $("#department").append("<optionvalue='"+deptId+"'>"+deptName+"</option>"); } } }); } }); $("#department").change(function(){ $("#employeeoption:not(:first)").remove(); vardepartment_id=$(this).val(); if(department_id!=""){ varurl="EmployeeServlet?method=listEmployees"; varargs={"department_id":department_id,"time":newDate()}; $.getJSON(url,function(data){ if(data.length==0){ alert("当前部门没有员工"); }else{ for(vari=0;i<data.length;i++){ varlastName=data[i].lastName; varemail=data[i].email; varsalary=data[i].salary; varemployeeId=data[i].employeeId; $("#employee").append("<optionvalue='"+employeeId+"'>"+lastName+"</option>"); } } }); } }); $("#employee").change(function(){ varemployeeId=$(this).val(); if(employeeId!=""){ varurl="EmployeeServlet?method=listEmployeeInfo"; varargs={"employeeId":employeeId,function(data){ if(data.length==0){ alert("数据丢失"); }else{ $("#employee_id").text(data.employeeId); $("#last_name").text(data.lastName); $("#email").text(data.email); $("#salary").text(data.salary); } }); } //} }); }) </script> </head> <body> <imgalt=""id="loading"src="${pageContext.request.contextPath}/images/loading.gif"style="display:none"> City: <selectid="city"> <optionvalue="">请选择...</option> <c:forEachitems="${locations}"var="location"> <optionvalue="${location.location_id}">${location.city}</option> </c:forEach> </select>Department: <selectid="department"> <optionvalue="">请选择...</option> </select>Employee: <selectid="employee"> <optionvalue="">请选择...</option> </select> <br/>员工编号: <spanid="employee_id"></span> <br/>姓名： <spanid="last_name"></span> <br/>email： <spanid="email"></span> <br/>薪水： <spanid="salary"></span> <br/> </body> </html>
源码http://yunpan.cn/cgephkTV2Tcmh （提取码：2492）
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