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显示错误结果的自定义toString(char)方法

tostring delimiter java

Matt · 技术社区 · 7 年前

    @Override
    public String toString() {
        return "\nCustomer Id: " + this.customerId +
                "\nName: " + this.customerName +
                "\nProjects: " + "\n" + getNumberedProjects();
    }

     public String toString(char delimiter) {
        final String QUOTE = "\"";
        final String EOLN = "\n";
        String output =  Integer.toString(this.customerId) + delimiter +
                         QUOTE + this.customerName + QUOTE + delimiter +
                         Integer.toString(this.customerProjects.size());

      output += EOLN + delimiter;
        for (Project project : customerProjects)
              output += EOLN + delimiter + QUOTE + project + QUOTE;
        output += EOLN;
        return output;
     }

这一部分叫做:

public void store(String filename, Repository repository) {
    try (PrintWriter output = new PrintWriter(filename)) {
        output.print(repository.toString(DELIMITER));
        output.close();
    } catch (FileNotFoundException ex) {
        Logger.getLogger(DAOTextImpl.class.getName()).log(Level.SEVERE, null, ex);
    }        
}

它创建了一个txt文件,如下所示:

但这正是我所期待的:

2 回复 | 直到 7 年前

Sunil 7 年前

请在toString方法中找到更正。让我们假设您的 Project 班级有三个 projectId , projectName 和 startDate 属性。

     public String toString(char delimiter) {
        final String QUOTE = "\"";
        final String EOLN = "\n";
        String output =   (this.customerId) + delimiter +
                         QUOTE + this.customerName + QUOTE + delimiter +
                         Integer.toString(this.customerProjects.size());

      output += EOLN ;
        for (Project project : customerProjects){
              output += QUOTE + project.getProjectId() + QUOTE;
              output +=   delimiter + QUOTE + project.getProjectName() + QUOTE;
              output +=   delimiter + QUOTE + project.getStartDate();
        output += EOLN;
        }
        return output;
     }

walen 7 年前

显然 toString() 方法来自 Project 类不会返回您期望它返回的内容。你也覆盖了吗?因为在这一行中:
```
output += EOLN + delimiter + QUOTE + project + QUOTE;
```
你好像在期待 project 翻译成
"\"" + project.getId() + "\",\"" + project.getName() + "\",\"" + project.getStart() + "\""
事实上,当它返回这样的结果时:
"\nProject ID: " + project.getId() + " Project Name: " + project.getName() + " Start: " + project.getStart() + "\n"
Project#toString() 让它归还你想要的东西。
你似乎在使用 QUOTE 而不是 EOLN output += EOLN + delimiter; 正在打印这个 ", 真实的 代码为 output += QUOTE + delimiter; . 可能是拼写错误,请更正。