Spring mvc 添加多行

Question

我需要你的帮助，因为标题说我在从 jsp 表单插入多行时遇到问题。该代码来自该网站的答案。

Controller

@ModelAttribute("programform")
public ProgramForm populatePojos() {
    // Don't forget to initialize the pojos list or else it won't work
    ProgramForm programform = new ProgramForm();
    List<Programs> programs = new ArrayList<Programs>();
    for(int i=0; i<2; i++) {
        programs.add(new Programs());

    }
    programform.setPrograms(programs);
    return programform;
}




@RequestMapping(value = "/createprog")
public ModelAndView tiles2(@ModelAttribute("programform") ProgramForm  programform,
        BindingResult result) {
    //Map<String, Object> model = new HashMap<String, Object>();
    //model.put("articles",  articleService.listArticles());

    return new ModelAndView("createprogram");
}


@RequestMapping(value = "/saveprogram", method = RequestMethod.POST)
public ModelAndView saveProgram(@ModelAttribute("programform") ProgramForm  programform,
        BindingResult result) {
    for(Programs programs : programform.getPrograms()) {
           System.out.println(programs.getProgram_id());
           articleService.addProgram(programs);
        }

jsp

 <c:url var="saveProgramUrl" value="/articles/saveprogram.html" />
<form:form modelAttribute="programform" method="POST" action="${saveProgramUrl}">
<table>
<tr>
            <th>ProgramId</th>
            <th>Date</th>
            <th>Type</th>
            <th>Start</th>
            <th>End</th>
            <th>Location</th>
            <th>User</th>
            <th>Program Name</th>
</tr>
    <tr> 
                <th><form:input path="programs[0].program_id" /></th>
                 <th> <form:input path="programs[0].date" id="datepick" class="date-pick"/>
        <script type="text/javascript">
            datepickr('datepick', { dateFormat: 'Y-m-d' });
        </script></th>
                <th><form:input path="programs[0].type" /></th>
                <th><form:input path="programs[0].start" /></th>
                <th><form:input path="programs[0].end" /></th>
                <th><form:input path="programs[0].location" /></th>
                <th><form:input path="programs[0].user_id" /></th>
                <th><form:input path="programs[0].program_name" /></th>
    </tr>
 <tr> 
                <th><form:input path="programs[1].program_id" /></th>
                 <th> <form:input path="programs[1].date" id="datepick" class="date-pick"/>
        <script type="text/javascript">
            datepickr('datepick', { dateFormat: 'Y-m-d' });
        </script></th>
                <th><form:input path="programs[1].type" /></th>
                <th><form:input path="programs[1].start" /></th>
                <th><form:input path="programs[1].end" /></th>
                <th><form:input path="programs[1].location" /></th>
                <th><form:input path="programs[1].user_id" /></th>
                <th><form:input path="programs[1].program_name" /></th>
    </tr>
</table>
<br/>
<input type="submit" value="Insert User" />
</form:form>

程序

    package net.roseindia.model;



import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "program")
public class Programs {




    @Id
    @Column(name = "Program_Id")
    private int program_id;
    @Column(name = "Date")
    private String date;
    @Column(name = "Duty_Type")
    private String type;
    @Column(name = "Duty_Start_Time")
    private String start;
    @Column(name = "Duty_End_Time")
    private String end;
    @Column(name = "Location")
    private String location;
    @Column(name = "User_Id")
    private int user_id;
    @Column(name = "Program_Name")
    private String program_name;


    public int getProgram_id() {
        return program_id;
    }


    public void setProgram_id(int program_id) {
        this.program_id = program_id;
    }


    public String getDate() {
        return date;
    }


    public void setDate(String date) {
        this.date = date;
    }


    public String getType() {
        return type;
    }


    public void setType(String type) {
        this.type = type;
    }




    public String getStart() {
        return start;
    }


    public void setStart(String start) {
        this.start = start;
    }


    public String getEnd() {
        return end;
    }


    public void setEnd(String end) {
        this.end = end;
    }


    public String getLocation() {
        return location;
    }


    public void setLocation(String location) {
        this.location = location;
    }


    public int getUser_id() {
        return user_id;
    }


    public void setUser_id(int user_id) {
        this.user_id = user_id;
    }


    public String getProgram_name() {
        return program_name;
    }


    public void setProgram_name(String program_name) {
        this.program_name = program_name;
    }


    public Programs() { 

    }





}

程序表单

package net.roseindia.model;

import java.util.List;

public class ProgramForm {



    private List<Programs> programs;

    public List<Programs> getPrograms() {
        return programs;
    }

    public void setPrograms(List<Programs> programs) {
        this.programs = programs;
    }


}

当我按下按钮将其保存到程序时，数据库中没有插入任何内容，我做错了什么？

Answer 1

要添加多行，您需要延迟初始化列表。请按照以下方式更改 @ModelAttribute("programform") 中的代码，然后重试。

@ModelAttribute("programform") 
public ProgramForm populatePojos() { 
    // Don't forget to initialize the pojos list or else it won't work 
    ProgramForm programform = new ProgramForm(); 
    List<Programs> programs = LazyList.decorate(new ArrayList<Programs>(), FactoryUtils.instantiateFactory(Programs.class));

    for(int i=0; i<2; i++) { 
        programs.add(new Programs()); 

    } 
    programform.setPrograms(programs); 
    return programform; 
}

通过如上所述初始化列表，您还可以使用 JavaScript 添加更多运行时字段，并可以将这些值绑定(bind)到您的列表中。

完成此更改后，如果它不起作用，那么您需要在 jsp 页面中进行更改。不要使用 use simple 标签，但不要忘记在 name 属性中指定与您在此处的 path 属性中指定的值相同的值。

希望这对您有帮助。干杯。